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Ecovyst Inc. – ‘10-K’ for 12/31/21 – ‘EX-101.SCH’

On:  Tuesday, 3/1/22, at 5:23pm ET   ·   For:  12/31/21   ·   Accession #:  1708035-22-6   ·   File #:  1-38221

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  As Of               Filer                 Filing    For·On·As Docs:Size

 3/01/22  Ecovyst Inc.                      10-K       12/31/21  181:24M

Annual Report   —   Form 10-K

Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   2.70M 
 2: EX-4.3      Instrument Defining the Rights of Security Holders  HTML     56K 
 6: EX-10.10    Material Contract                                   HTML     76K 
 7: EX-10.11    Material Contract                                   HTML     76K 
 8: EX-10.38    Material Contract                                   HTML     74K 
 3: EX-10.7     Material Contract                                   HTML     76K 
 4: EX-10.8     Material Contract                                   HTML     64K 
 5: EX-10.9     Material Contract                                   HTML     61K 
 9: EX-21.1     Subsidiaries List                                   HTML     52K 
10: EX-23.1     Consent of Expert or Counsel                        HTML     44K 
11: EX-23.2     Consent of Expert or Counsel                        HTML     44K 
12: EX-31.1     Certification -- §302 - SOA'02                      HTML     49K 
13: EX-31.2     Certification -- §302 - SOA'02                      HTML     49K 
14: EX-32.1     Certification -- §906 - SOA'02                      HTML     46K 
15: EX-32.2     Certification -- §906 - SOA'02                      HTML     46K 
21: R1          Cover                                               HTML    106K 
22: R2          Audit Information                                   HTML     50K 
23: R3          Consolidated Statements of Income                   HTML    180K 
24: R4          Consolidated Statements of Comprehensive Income     HTML     81K 
                (Loss)                                                           
25: R5          Consolidated Balance Sheets                         HTML    207K 
26: R6          Consolidated Statements of Stockholders? Equity     HTML    131K 
27: R7          Consolidated Statements of Cash Flows               HTML    191K 
28: R8          Consolidated Statements of Stockholders? Equity     HTML     46K 
                (Parenthetical)                                                  
29: R9          Background and Basis of Presentation                HTML     54K 
30: R10         Summary of Significant Accounting Policies          HTML     90K 
31: R11         New Accounting Standards                            HTML     61K 
32: R12         Performance Materials Divestiture                   HTML     92K 
33: R13         Performance Chemicals Divestiture                   HTML    109K 
34: R14         Acquisition                                         HTML     87K 
35: R15         Revenue from Contracts with Customers               HTML    109K 
36: R16         Fair Value Measurements                             HTML     69K 
37: R17         Stockholders' Equity                                HTML    152K 
38: R18         Other Operating Expense, Net                        HTML     59K 
39: R19         Inventories, Net                                    HTML     58K 
40: R20         Investments in Affiliated Companies                 HTML     79K 
41: R21         Property, Plant and Equipment                       HTML     57K 
42: R22         Leases                                              HTML    146K 
43: R23         Reportable Segments                                 HTML    139K 
44: R24         Goodwill and Other Intangible Assets                HTML    103K 
45: R25         Accrued Liabilities                                 HTML     59K 
46: R26         Long-term Debt                                      HTML     89K 
47: R27         Other Long-term Liabilities                         HTML     55K 
48: R28         Financial Instruments                               HTML    117K 
49: R29         Income Taxes                                        HTML    151K 
50: R30         Benefit Plans                                       HTML    302K 
51: R31         Stock-Based Compensation                            HTML    158K 
52: R32         Earnings per Share                                  HTML     79K 
53: R33         Commitments and Contingent Liabilities              HTML     52K 
54: R34         Related Party Transactions                          HTML     52K 
55: R35         Quarterly Financial Summary (Unaudited)             HTML    130K 
56: R36         Supplemental Cash Flow Information                  HTML     67K 
57: R37         Subsequent Events                                   HTML     47K 
58: R38         Schedule I - Condensed Financial Information of     HTML    108K 
                Parent                                                           
59: R39         Summary of Significant Accounting Policies Summary  HTML    167K 
                of Significant Accounting Policies (Policies)                    
60: R40         Performance Materials Divestiture (Tables)          HTML     92K 
61: R41         Performance Chemicals Divestiture (Tables)          HTML    106K 
62: R42         Chem32 Acquisition (Tables)                         HTML     85K 
63: R43         Revenue from Contracts with Customers Revenue from  HTML     93K 
                Contracts with Customers (Tables)                                
64: R44         Fair Value Measurements (Tables)                    HTML     62K 
65: R45         Stockholders' Equity (Tables)                       HTML    144K 
66: R46         Other Operating Expense, Net (Tables)               HTML     59K 
67: R47         Inventories (Tables)                                HTML     58K 
68: R48         Investments in Affiliated Companies (Tables)        HTML     75K 
69: R49         Property, Plant and Equipment (Tables)              HTML     56K 
70: R50         Leases (Tables)                                     HTML    100K 
71: R51         Reportable Segments (Tables)                        HTML    141K 
72: R52         Goodwill and Other Intangible Assets Goodwill and   HTML    139K 
                Other Intangible Assets (Tables)                                 
73: R53         Accrued Liabilities Accrued Liabilities (Tables)    HTML     59K 
74: R54         Long-term Debt (Tables)                             HTML     72K 
75: R55         Other Long-term Liabilities Other Long-term         HTML     55K 
                Liabilities (Tables)                                             
76: R56         Financial Instruments (Tables)                      HTML    114K 
77: R57         Income Taxes (Tables)                               HTML    157K 
78: R58         Benefit Plans (Tables)                              HTML    312K 
79: R59         Stock-Based Compensation Stock-Based Compensation   HTML    137K 
                (Tables)                                                         
80: R60         Earnings per Share (Tables)                         HTML     81K 
81: R61         Quarterly Financial Summary (Unaudited) (Tables)    HTML    130K 
82: R62         Supplemental Cash Flow Information (Tables)         HTML     80K 
83: R63         Schedule I - Condensed Financial Information of     HTML    104K 
                Parent (Tables)                                                  
84: R64         Background and Basis of Presentation (Details)      HTML     55K 
85: R65         Summary of Significant Accounting Policies -        HTML     69K 
                Narratives (Details)                                             
86: R66         Performance Materials Divestiture - Narrative       HTML     59K 
                (Details)                                                        
87: R67         Performance Materials Divestiture - Reconciliation  HTML     62K 
                of Loss (Details)                                                
88: R68         Performance Materials Divestiture - Income          HTML    115K 
                Information (Details)                                            
89: R69         Performance Materials Divestiture - Assets and      HTML    116K 
                Liabilities (Details)                                            
90: R70         Performance Chemicals Divestiture - Narrative       HTML     54K 
                (Details)                                                        
91: R71         Performance Chemicals Divestiture - Reconciliation  HTML    126K 
                of Loss (Details)                                                
92: R72         Performance Chemicals Divestiture - Income          HTML    118K 
                Information (Details)                                            
93: R73         Performance Chemicals Divestiture - Assets and      HTML    116K 
                Liabilities (Details)                                            
94: R74         Performance Chemicals Divestiture - Financing       HTML     50K 
                Obligation (Details)                                             
95: R75         Acquisition Narrative (Details)                     HTML     68K 
96: R76         Chem32 Purchase Price Allocation (Details)          HTML    126K 
97: R77         Intangible Asset Acquisitions (Details)             HTML     57K 
98: R78         Revenue from Contracts with Customers Contract      HTML     49K 
                Assets and Liabilities (Details)                                 
99: R79         Revenue from Contracts with Customers               HTML     91K 
                Disaggregated Revenue (Details)                                  
100: R80         Fair Value Measurements - Assets and Liabilities    HTML     55K  
                Measured at Fair Value on a Recurring Basis                      
                (Details)                                                        
101: R81         Stockholders' Equity - Components of AOCI           HTML     69K  
                (Details)                                                        
102: R82         Stockholders' Equity - Pre-tax and After-tax        HTML     79K  
                Components of Other Comprehensive Income (Loss)                  
                (Details)                                                        
103: R83         Stockholders' Equity - Change by Component          HTML     84K  
                (Details)                                                        
104: R84         Stockholders' Equity - Reclassifications out of     HTML     98K  
                AOCI (Details)                                                   
105: R85         Stock Repurchase Program (Details)                  HTML     57K  
106: R86         Dividends Paid (Details)                            HTML     46K  
107: R87         Other Operating Expense, Net (Details)              HTML     59K  
108: R88         Inventories (Details)                               HTML     59K  
109: R89         Inventories, Net - Narratives (Details)             HTML     47K  
110: R90         Investments in Affiliated Companies - Narratives    HTML     64K  
                (Details)                                                        
111: R91         Investments in Affiliated Companies - Ownership     HTML     50K  
                Percentage (Details)                                             
112: R92         Investments in Affiliated Companies - Summarized    HTML     81K  
                Balance Sheet (Details)                                          
113: R93         Investments in Affiliated Companies - Summarized    HTML     82K  
                Income Statement (Details)                                       
114: R94         Investments in Affiliated Companies - Rollforward   HTML     56K  
                (Details)                                                        
115: R95         Property, Plant and Equipment (Details)             HTML     62K  
116: R96         Property, Plant and Equipment - Narratives          HTML     46K  
                (Details)                                                        
117: R97         Leases - Narratives (Details)                       HTML     48K  
118: R98         Leases - Right-of-Use Lease Assets and Lease        HTML     69K  
                Liabilities (Details)                                            
119: R99         Leases - Remaining Average Weighted Average Lease   HTML     56K  
                Term and Discount Rates (Details)                                
120: R100        Leases - Lease Maturity Schedule - ASC 842          HTML     84K  
                (Details)                                                        
121: R101        Leases - Other Lease Information (Details)          HTML     58K  
122: R102        Reportable Segments - Narratives (Details)          HTML     48K  
123: R103        Reportable Segments - Summary Financial             HTML     84K  
                Information by Reportable Segment (Details)                      
124: R104        Reportable Segments - Reconciliation of Net Income  HTML     95K  
                to Adjusted EBITDA (Details)                                     
125: R105        Reportable Segments - Capital Expenditures          HTML     56K  
                (Details)                                                        
126: R106        Reportable Segments - Sales by Geography (Details)  HTML     65K  
127: R107        Reportable Segments - Assets by Geography           HTML     51K  
                (Details)                                                        
128: R108        Goodwill and Other Intangible Assets - Goodwill     HTML     58K  
                Rollforward (Details)                                            
129: R109        Goodwill and Other Intangible Assets - Narratives   HTML     53K  
                (Details)                                                        
130: R110        Goodwill and Other Intangible Assets - Schedule of  HTML     96K  
                Intangible Assets (Details)                                      
131: R111        Goodwill and Other Intangible Assets - Future       HTML     60K  
                Amortization (Details)                                           
132: R112        Accrued Liabilities Accrued Liabilities (Details)   HTML     68K  
133: R113        Long-term Debt (Details)                            HTML     78K  
134: R114        Long-term Debt - Senior Secured Credit Facilities   HTML    174K  
                (Details)                                                        
135: R115        Long-term Debt - Secured and Unsecured Notes        HTML     67K  
                (Details)                                                        
136: R116        Long-term Debt - Aggregate Long-term Debt           HTML     65K  
                Maturities (Details)                                             
137: R117        Other Long-term Liabilities Other Long-term         HTML     59K  
                Liabilities (Details)                                            
138: R118        Financial Instruments - Narratives (Details)        HTML     98K  
139: R119        Financial Instruments - Fair Value (Details)        HTML     62K  
140: R120        Financial Instruments - Effect on Other             HTML     54K  
                Comprehensive Income (Details)                                   
141: R121        Financial Instruments - Cash Flow Hedge Impact on   HTML     54K  
                Statements of Income (Details)                                   
142: R122        Financial Instruments - Net Investment Hedge        HTML     58K  
                Impact on AOCI (Details)                                         
143: R123        Income Taxes - Narratives (Details)                 HTML     62K  
144: R124        Income Taxes - Income (loss) before Income Taxes    HTML     54K  
                and Noncontrolling interest (Details)                            
145: R125        Income Taxes - Provision for Income Tax (Details)   HTML     73K  
146: R126        Income Taxes - Reconciliation of Statutory Tax      HTML     74K  
                Rate (Details)                                                   
147: R127        Income Taxes - Components of Deferred Tax Asset     HTML     89K  
                (Liability) (Details)                                            
148: R128        Income Taxes - Change in Unrecognized Tax Position  HTML     51K  
                (Details)                                                        
149: R129        Income Taxes - Payment for Taxes (Details)          HTML     53K  
150: R130        Benefit Plans - Change in Benefit Obligation and    HTML    137K  
                Plan Assets (Details)                                            
151: R131        Benefit Plans - Recognized on the Balance Sheet     HTML     65K  
                (Details)                                                        
152: R132        Benefit Plans - Accumulated Other Comprehensive     HTML     66K  
                Income (Details)                                                 
153: R133        Benefit Plans - Net Periodic Benefit Cost           HTML     77K  
                (Details)                                                        
154: R134        Benefit Plans - Accumulated Benefit Obligation      HTML     62K  
                (Details)                                                        
155: R135        Benefit Plans - Projected Benefit Obligation        HTML     59K  
                (Details)                                                        
156: R136        Benefit Plans - Weighted Average Assumptions for    HTML     56K  
                Pension Obligation (Details)                                     
157: R137        Benefit Plans - Weighted Average Assumptions for    HTML     60K  
                Net Periodic Cost (Details)                                      
158: R138        Benefit Plans - Plan Assets (Details)               HTML     99K  
159: R139        Benefit Plans - Benefit Plan, Future Payments       HTML     66K  
                (Details)                                                        
160: R140        Benefit Plans - Defined Contribution Plan           HTML     46K  
                (Details)                                                        
161: R141        Stock-Based Compensation - Narratives (Details)     HTML    108K  
162: R142        Stock-Based Compensation - Stock Option Activity    HTML     92K  
                (Details)                                                        
163: R143        Stock-Based Compensation - Stock Option             HTML     59K  
                Assumptions and Methodology (Details)                            
164: R144        Stock-Based Compensation - Restricted Stock Awards  HTML     85K  
                and Units (Details)                                              
165: R145        Earnings per Share - Reconciliation from Basic to   HTML     54K  
                Diluted Weighted Average Shares Outstanding                      
                (Details)                                                        
166: R146        Earnings per Share - Reconciliation of Net Income   HTML     81K  
                (Details)                                                        
167: R147        Earnings per Share - Anti-dilutive Shares           HTML     57K  
                (Details)                                                        
168: R148        Commitments and Contingent Liabilities -            HTML     54K  
                Narratives (Details)                                             
169: R149        Related Party Transactions (Details)                HTML     63K  
170: R150        Quarterly Financial Summary (Unaudited) (Details)   HTML    152K  
171: R151        Supplemental Cash Flow Information (Details)        HTML     56K  
172: R152        Supplemental Cash Flow Information - Cash and       HTML     56K  
                Restricted Cash Reconciliation (Details)                         
173: R153        Schedule I - Condensed Statements of Income         HTML     86K  
                (Details)                                                        
174: R154        Schedule I - Condensed Balance Sheet (Details)      HTML     99K  
175: R155        Schedule I - Condensed Balance Sheet Shares Data    HTML     69K  
                (Details)                                                        
176: R156        Schedule I - Condensed Statement of Cash Flow       HTML    101K  
                (Details)                                                        
179: XML         IDEA XML File -- Filing Summary                      XML    332K  
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178: EXCEL       IDEA Workbook of Financial Reports                  XLSX    254K  
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16: EX-101.SCH  XBRL Schema -- ecvt-20211231                         XSD    336K 
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181: ZIP         XBRL Zipped Folder -- 0001708035-22-000006-xbrl      Zip   1.08M  


‘EX-101.SCH’   —   XBRL Schema — ecvt-20211231


This Exhibit is an XBRL XML File.


                                                                                                                                                                                
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<link:definition> 240054003 - Disclosure - Summary of Significant Accounting Policies - Narratives (Details) </link:definition>
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<link:usedOn> link:calculationLink </link:usedOn>
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<link:usedOn> link:calculationLink </link:usedOn>
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<link:definition> 210071004 - Disclosure - Performance Materials Divestiture </link:definition>
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<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceMaterialsDivestitureTables" roleURI="http://www.ecovyst.com/role/PerformanceMaterialsDivestitureTables">
<link:definition> 230083001 - Disclosure - Performance Materials Divestiture (Tables) </link:definition>
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<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceMaterialsDivestitureNarrativeDetails" roleURI="http://www.ecovyst.com/role/PerformanceMaterialsDivestitureNarrativeDetails">
<link:definition> 240094004 - Disclosure - Performance Materials Divestiture - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceMaterialsDivestitureReconciliationofLossDetails" roleURI="http://www.ecovyst.com/role/PerformanceMaterialsDivestitureReconciliationofLossDetails">
<link:definition> 240104005 - Disclosure - Performance Materials Divestiture - Reconciliation of Loss (Details) </link:definition>
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<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceMaterialsDivestitureIncomeInformationDetails" roleURI="http://www.ecovyst.com/role/PerformanceMaterialsDivestitureIncomeInformationDetails">
<link:definition> 240114006 - Disclosure - Performance Materials Divestiture - Income Information (Details) </link:definition>
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<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:definition> 240124007 - Disclosure - Performance Materials Divestiture - Assets and Liabilities (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceChemicalsDivestiture" roleURI="http://www.ecovyst.com/role/PerformanceChemicalsDivestiture">
<link:definition> 210131005 - Disclosure - Performance Chemicals Divestiture </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceChemicalsDivestitureTables" roleURI="http://www.ecovyst.com/role/PerformanceChemicalsDivestitureTables">
<link:definition> 230143002 - Disclosure - Performance Chemicals Divestiture (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceChemicalsDivestitureNarrativeDetails" roleURI="http://www.ecovyst.com/role/PerformanceChemicalsDivestitureNarrativeDetails">
<link:definition> 240154008 - Disclosure - Performance Chemicals Divestiture - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceChemicalsDivestitureReconciliationofLossDetails" roleURI="http://www.ecovyst.com/role/PerformanceChemicalsDivestitureReconciliationofLossDetails">
<link:definition> 240164009 - Disclosure - Performance Chemicals Divestiture - Reconciliation of Loss (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceChemicalsDivestitureIncomeInformationDetails" roleURI="http://www.ecovyst.com/role/PerformanceChemicalsDivestitureIncomeInformationDetails">
<link:definition> 240174010 - Disclosure - Performance Chemicals Divestiture - Income Information (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceChemicalsDivestitureAssetsandLiabilitiesDetails" roleURI="http://www.ecovyst.com/role/PerformanceChemicalsDivestitureAssetsandLiabilitiesDetails">
<link:definition> 240184011 - Disclosure - Performance Chemicals Divestiture - Assets and Liabilities (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PerformanceChemicalsDivestitureFinancingObligationDetails" roleURI="http://www.ecovyst.com/role/PerformanceChemicalsDivestitureFinancingObligationDetails">
<link:definition> 240194012 - Disclosure - Performance Chemicals Divestiture - Financing Obligation (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="Acquisition" roleURI="http://www.ecovyst.com/role/Acquisition">
<link:definition> 210201006 - Disclosure - Acquisition </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="Chem32AcquisitionTables" roleURI="http://www.ecovyst.com/role/Chem32AcquisitionTables">
<link:definition> 230213003 - Disclosure - Chem32 Acquisition (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="AcquisitionNarrativeDetails" roleURI="http://www.ecovyst.com/role/AcquisitionNarrativeDetails">
<link:definition> 240224013 - Disclosure - Acquisition Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="Chem32PurchasePriceAllocationDetails" roleURI="http://www.ecovyst.com/role/Chem32PurchasePriceAllocationDetails">
<link:definition> 240234014 - Disclosure - Chem32 Purchase Price Allocation (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="IntangibleAssetAcquisitionsDetails" roleURI="http://www.ecovyst.com/role/IntangibleAssetAcquisitionsDetails">
<link:definition> 240244015 - Disclosure - Intangible Asset Acquisitions (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="RevenuefromContractswithCustomers" roleURI="http://www.ecovyst.com/role/RevenuefromContractswithCustomers">
<link:definition> 210251007 - Disclosure - Revenue from Contracts with Customers </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="RevenuefromContractswithCustomersRevenuefromContractswithCustomersTables" roleURI="http://www.ecovyst.com/role/RevenuefromContractswithCustomersRevenuefromContractswithCustomersTables">
<link:definition> 230263004 - Disclosure - Revenue from Contracts with Customers Revenue from Contracts with Customers (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="RevenuefromContractswithCustomersContractAssetsandLiabilitiesDetails" roleURI="http://www.ecovyst.com/role/RevenuefromContractswithCustomersContractAssetsandLiabilitiesDetails">
<link:definition> 240274016 - Disclosure - Revenue from Contracts with Customers Contract Assets and Liabilities (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="RevenuefromContractswithCustomersDisaggregatedRevenueDetails" roleURI="http://www.ecovyst.com/role/RevenuefromContractswithCustomersDisaggregatedRevenueDetails">
<link:definition> 240284017 - Disclosure - Revenue from Contracts with Customers Disaggregated Revenue (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="FairValueMeasurements" roleURI="http://www.ecovyst.com/role/FairValueMeasurements">
<link:definition> 210291008 - Disclosure - Fair Value Measurements </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="FairValueMeasurementsTables" roleURI="http://www.ecovyst.com/role/FairValueMeasurementsTables">
<link:definition> 230303005 - Disclosure - Fair Value Measurements (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="FairValueMeasurementsAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails" roleURI="http://www.ecovyst.com/role/FairValueMeasurementsAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails">
<link:definition> 240314018 - Disclosure - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="StockholdersEquity" roleURI="http://www.ecovyst.com/role/StockholdersEquity">
<link:definition> 210321009 - Disclosure - Stockholders' Equity </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="StockholdersEquityTables" roleURI="http://www.ecovyst.com/role/StockholdersEquityTables">
<link:definition> 230333006 - Disclosure - Stockholders' Equity (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="StockholdersEquityComponentsofAOCIDetails" roleURI="http://www.ecovyst.com/role/StockholdersEquityComponentsofAOCIDetails">
<link:definition> 240344019 - Disclosure - Stockholders' Equity - Components of AOCI (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="StockholdersEquityPretaxandAftertaxComponentsofOtherComprehensiveIncomeLossDetails" roleURI="http://www.ecovyst.com/role/StockholdersEquityPretaxandAftertaxComponentsofOtherComprehensiveIncomeLossDetails">
<link:definition> 240354020 - Disclosure - Stockholders' Equity - Pre-tax and After-tax Components of Other Comprehensive Income (Loss) (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="StockholdersEquityChangebyComponentDetails" roleURI="http://www.ecovyst.com/role/StockholdersEquityChangebyComponentDetails">
<link:definition> 240364021 - Disclosure - Stockholders' Equity - Change by Component (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="StockholdersEquityReclassificationsoutofAOCIDetails" roleURI="http://www.ecovyst.com/role/StockholdersEquityReclassificationsoutofAOCIDetails">
<link:definition> 240374022 - Disclosure - Stockholders' Equity - Reclassifications out of AOCI (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="StockRepurchaseProgramDetails" roleURI="http://www.ecovyst.com/role/StockRepurchaseProgramDetails">
<link:definition> 240384023 - Disclosure - Stock Repurchase Program (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="DividendsPaidDetails" roleURI="http://www.ecovyst.com/role/DividendsPaidDetails">
<link:definition> 240394024 - Disclosure - Dividends Paid (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="OtherOperatingExpenseNet" roleURI="http://www.ecovyst.com/role/OtherOperatingExpenseNet">
<link:definition> 210401010 - Disclosure - Other Operating Expense, Net </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="OtherOperatingExpenseNetTables" roleURI="http://www.ecovyst.com/role/OtherOperatingExpenseNetTables">
<link:definition> 230413007 - Disclosure - Other Operating Expense, Net (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="OtherOperatingExpenseNetDetails" roleURI="http://www.ecovyst.com/role/OtherOperatingExpenseNetDetails">
<link:definition> 240424025 - Disclosure - Other Operating Expense, Net (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InventoriesNet" roleURI="http://www.ecovyst.com/role/InventoriesNet">
<link:definition> 210431011 - Disclosure - Inventories, Net </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InventoriesTables" roleURI="http://www.ecovyst.com/role/InventoriesTables">
<link:definition> 230443008 - Disclosure - Inventories (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InventoriesDetails" roleURI="http://www.ecovyst.com/role/InventoriesDetails">
<link:definition> 240454026 - Disclosure - Inventories (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InventoriesDetails_1" roleURI="http://www.ecovyst.com/role/InventoriesDetails_1">
<link:definition> 240454026 - Disclosure - Inventories (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="InventoriesNetNarrativesDetails" roleURI="http://www.ecovyst.com/role/InventoriesNetNarrativesDetails">
<link:definition> 240464027 - Disclosure - Inventories, Net - Narratives (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="InvestmentsinAffiliatedCompanies" roleURI="http://www.ecovyst.com/role/InvestmentsinAffiliatedCompanies">
<link:definition> 210471012 - Disclosure - Investments in Affiliated Companies </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InvestmentsinAffiliatedCompaniesTables" roleURI="http://www.ecovyst.com/role/InvestmentsinAffiliatedCompaniesTables">
<link:definition> 230483009 - Disclosure - Investments in Affiliated Companies (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InvestmentsinAffiliatedCompaniesNarrativesDetails" roleURI="http://www.ecovyst.com/role/InvestmentsinAffiliatedCompaniesNarrativesDetails">
<link:definition> 240494028 - Disclosure - Investments in Affiliated Companies - Narratives (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InvestmentsinAffiliatedCompaniesOwnershipPercentageDetails" roleURI="http://www.ecovyst.com/role/InvestmentsinAffiliatedCompaniesOwnershipPercentageDetails">
<link:definition> 240504029 - Disclosure - Investments in Affiliated Companies - Ownership Percentage (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="InvestmentsinAffiliatedCompaniesSummarizedBalanceSheetDetails" roleURI="http://www.ecovyst.com/role/InvestmentsinAffiliatedCompaniesSummarizedBalanceSheetDetails">
<link:definition> 240514030 - Disclosure - Investments in Affiliated Companies - Summarized Balance Sheet (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="InvestmentsinAffiliatedCompaniesSummarizedIncomeStatementDetails" roleURI="http://www.ecovyst.com/role/InvestmentsinAffiliatedCompaniesSummarizedIncomeStatementDetails">
<link:definition> 240524031 - Disclosure - Investments in Affiliated Companies - Summarized Income Statement (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="InvestmentsinAffiliatedCompaniesRollforwardDetails" roleURI="http://www.ecovyst.com/role/InvestmentsinAffiliatedCompaniesRollforwardDetails">
<link:definition> 240534032 - Disclosure - Investments in Affiliated Companies - Rollforward (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="PropertyPlantandEquipment" roleURI="http://www.ecovyst.com/role/PropertyPlantandEquipment">
<link:definition> 210541013 - Disclosure - Property, Plant and Equipment </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="PropertyPlantandEquipmentTables" roleURI="http://www.ecovyst.com/role/PropertyPlantandEquipmentTables">
<link:definition> 230553010 - Disclosure - Property, Plant and Equipment (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="PropertyPlantandEquipmentDetails" roleURI="http://www.ecovyst.com/role/PropertyPlantandEquipmentDetails">
<link:definition> 240564033 - Disclosure - Property, Plant and Equipment (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType id="PropertyPlantandEquipmentNarrativesDetails" roleURI="http://www.ecovyst.com/role/PropertyPlantandEquipmentNarrativesDetails">
<link:definition> 240574034 - Disclosure - Property, Plant and Equipment - Narratives (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="Leases" roleURI="http://www.ecovyst.com/role/Leases">
<link:definition> 210581014 - Disclosure - Leases </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="LeasesTables" roleURI="http://www.ecovyst.com/role/LeasesTables">
<link:definition> 230593011 - Disclosure - Leases (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="LeasesNarrativesDetails" roleURI="http://www.ecovyst.com/role/LeasesNarrativesDetails">
<link:definition> 240604035 - Disclosure - Leases - Narratives (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="LeasesRightofUseLeaseAssetsandLeaseLiabilitiesDetails" roleURI="http://www.ecovyst.com/role/LeasesRightofUseLeaseAssetsandLeaseLiabilitiesDetails">
<link:definition> 240614036 - Disclosure - Leases - Right-of-Use Lease Assets and Lease Liabilities (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="LeasesRemainingAverageWeightedAverageLeaseTermandDiscountRatesDetails" roleURI="http://www.ecovyst.com/role/LeasesRemainingAverageWeightedAverageLeaseTermandDiscountRatesDetails">
<link:definition> 240624037 - Disclosure - Leases - Remaining Average Weighted Average Lease Term and Discount Rates (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
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<link:roleType id="LeasesLeaseMaturityScheduleASC842Details" roleURI="http://www.ecovyst.com/role/LeasesLeaseMaturityScheduleASC842Details">
<link:definition> 240634038 - Disclosure - Leases - Lease Maturity Schedule - ASC 842 (Details) </link:definition>
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<xs:element id="ecvt_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPrepaidandOtherCurrentAssets" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPrepaidandOtherCurrentAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_EcoServicesPensionEquityPlanMember" abstract="true" name="EcoServicesPensionEquityPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_DefinedBenefitPlanBenefitObligationExpensesPaid" abstract="false" name="DefinedBenefitPlanBenefitObligationExpensesPaid" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_ZeolystInternationalMember" abstract="true" name="ZeolystInternationalMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_WeightedAverageRemainingLeaseTermAbstract" abstract="true" name="WeightedAverageRemainingLeaseTermAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
<xs:element id="ecvt_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssets" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_November2018InterestRateCapMember" abstract="true" name="November2018InterestRateCapMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_PerformanceStockUnitsGrantsInPeriodWeightedAverageGrantDateFairValue" abstract="false" name="PerformanceStockUnitsGrantsInPeriodWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
<xs:element id="ecvt_ZeolystC.V.Member" abstract="true" name="ZeolystC.V.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesNoncurrent" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentLongtermDebt" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentLongtermDebt" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_July2020InterestRateCapMember" abstract="true" name="July2020InterestRateCapMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_PerformanceMaterialsMember" abstract="true" name="PerformanceMaterialsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_TransitionServicesAgreementExtensionTerm" abstract="false" name="TransitionServicesAgreementExtensionTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
<xs:element id="ecvt_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNetAssetsAcquired" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNetAssetsAcquired" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_ScheduleofTaxPaymentsTableTextBlock" abstract="false" name="ScheduleofTaxPaymentsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
<xs:element id="ecvt_ActuarialGainLossChangesduetoMortality" abstract="false" name="ActuarialGainLossChangesduetoMortality" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_AccumulatedTranslationAdjustmentMemberMember" abstract="true" name="AccumulatedTranslationAdjustmentMemberMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_CatalystTechnologiesMember" abstract="true" name="CatalystTechnologiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_TransitionServiceAgreementIncome" abstract="false" name="TransitionServiceAgreementIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_PerformanceStockUnitsMember" abstract="true" name="PerformanceStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_IndefiniteLivedIntangibleAssetsExcludingGoodwillNet" abstract="false" name="IndefiniteLivedIntangibleAssetsExcludingGoodwillNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_July2016InterestRateCapMember" abstract="true" name="July2016InterestRateCapMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_DebtInstrumentVariableRateFloor" abstract="false" name="DebtInstrumentVariableRateFloor" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
<xs:element id="ecvt_DeferredTaxAssetsOperatingLeaseLiability" abstract="false" name="DeferredTaxAssetsOperatingLeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_ProductDemonstrationCostsMember" abstract="true" name="ProductDemonstrationCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_InterestIncomeExpenseMember" abstract="true" name="InterestIncomeExpenseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_AccumulatedDefinedBenefitPlansAdjustmentMemberMember" abstract="true" name="AccumulatedDefinedBenefitPlansAdjustmentMemberMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_EquityMethodInvestmentsRollForward" abstract="true" name="EquityMethodInvestmentsRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
<xs:element id="ecvt_DisposalGroupsIncludingDiscontinuedOperationsDisclosureOfPerformanceChemicalsTextBlock" abstract="false" name="DisposalGroupsIncludingDiscontinuedOperationsDisclosureOfPerformanceChemicalsTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
<xs:element id="ecvt_CashpaidforamountsincludedinthemeasurementofleaseliabilitiesAbstract" abstract="true" name="CashpaidforamountsincludedinthemeasurementofleaseliabilitiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
<xs:element id="ecvt_EarningsBeforeInterestTaxesDepreciationAndAmortization" abstract="false" name="EarningsBeforeInterestTaxesDepreciationAndAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_PQHoldingsEcoServicesMember" abstract="true" name="PQHoldingsEcoServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_LesseeRemainingLeaseTerm" abstract="false" name="LesseeRemainingLeaseTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
<xs:element id="ecvt_RightofUseAssetsObtainedinExchangeforNewLeaseLiabilitiesNonCashAbstract" abstract="true" name="RightofUseAssetsObtainedinExchangeforNewLeaseLiabilitiesNonCashAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
<xs:element id="ecvt_FivePointSevenFivePercentSeniorUnsecuredNotesdue2025Member" abstract="true" name="FivePointSevenFivePercentSeniorUnsecuredNotesdue2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_A2016TermLoanFacilityMember" abstract="true" name="A2016TermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_LineofCreditFacilityPotentialCommitmentFeePercentage" abstract="false" name="LineofCreditFacilityPotentialCommitmentFeePercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
<xs:element id="ecvt_SharebasedCompensationAwardTrancheFourMember" abstract="true" name="SharebasedCompensationAwardTrancheFourMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_SummaryofSignificantAccountingPoliciesTableLineItems" abstract="true" name="SummaryofSignificantAccountingPoliciesTableLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
<xs:element id="ecvt_ReclassificationFromAOCIAttributableToDisposalOfBusiness" abstract="false" name="ReclassificationFromAOCIAttributableToDisposalOfBusiness" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_InventoryValuationInFIFOLowerThanLIFO" abstract="false" name="InventoryValuationInFIFOLowerThanLIFO" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_RevenueShippingAndHandlingPolicyPolicyTextBlock" abstract="false" name="RevenueShippingAndHandlingPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
<xs:element id="ecvt_DefinedBenefitPlanAmountsforAssetLiabilityandAccumulatedOtherComprehensiveIncomeRecognizedinStatementofFinancialPosition" abstract="false" name="DefinedBenefitPlanAmountsforAssetLiabilityandAccumulatedOtherComprehensiveIncomeRecognizedinStatementofFinancialPosition" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_CashandRestrictedCashReconciliationAbstract" abstract="true" name="CashandRestrictedCashReconciliationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
<xs:element id="ecvt_PerformanceStockUnitFairValueAssumptionsExpectedDividendRate" abstract="false" name="PerformanceStockUnitFairValueAssumptionsExpectedDividendRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
<xs:element id="ecvt_DisposalGroupIncludingDiscontinuedOperationNetAssetsDerecognizedOnDisposal" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationNetAssetsDerecognizedOnDisposal" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_DeferredTaxLiabilitiesOperatingLeaseRightofuseAssets" abstract="false" name="DeferredTaxLiabilitiesOperatingLeaseRightofuseAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_TransitionServicesAgreementNumberOfExtensionsAvailable" abstract="false" name="TransitionServicesAgreementNumberOfExtensionsAvailable" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
<xs:element id="ecvt_NetGainLossOnDispositionOfAssets" abstract="false" name="NetGainLossOnDispositionOfAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_Operatingandfinancerightofuseleaseassetstotal" abstract="false" name="Operatingandfinancerightofuseleaseassetstotal" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_IndustrialandChemicalProcessMember" abstract="true" name="IndustrialandChemicalProcessMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_January2022InterestRateCapExpiringOctober2025Member" abstract="true" name="January2022InterestRateCapExpiringOctober2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_A2021MonteCarloSimulationMember" abstract="true" name="A2021MonteCarloSimulationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_PerformanceStockUnitFairValueAssumptionsRiskFreeInterestRate" abstract="false" name="PerformanceStockUnitFairValueAssumptionsRiskFreeInterestRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
<xs:element id="ecvt_ActuarialGainLossChangesduetoDiscountRates" abstract="false" name="ActuarialGainLossChangesduetoDiscountRates" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_EcoServicesHourlyPensionPlanMember" abstract="true" name="EcoServicesHourlyPensionPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_TransitionServicesAgreementTerm" abstract="false" name="TransitionServicesAgreementTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
<xs:element id="ecvt_PerformanceStockUnitFairValueAssumptionsExpectedTerm" abstract="false" name="PerformanceStockUnitFairValueAssumptionsExpectedTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
<xs:element id="ecvt_OperatingandFinanceLeaseLiabilitiesTotal" abstract="false" name="OperatingandFinanceLeaseLiabilitiesTotal" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization" abstract="false" name="AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_AccruedCompensationandBonusCurrent" abstract="false" name="AccruedCompensationandBonusCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_PerformanceStockUnitFairValueAssumptionsExpectedVolatilityRate" abstract="false" name="PerformanceStockUnitFairValueAssumptionsExpectedVolatilityRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
<xs:element id="ecvt_SparePartsPolicyPolicyTextBlock" abstract="false" name="SparePartsPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
<xs:element id="ecvt_PaymentsUnderFinancingArrangement" abstract="false" name="PaymentsUnderFinancingArrangement" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_January2022InterestRateCapsMember" abstract="true" name="January2022InterestRateCapsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_OtherInsurancePoliciesMember" abstract="true" name="OtherInsurancePoliciesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_ProceedsFromFailedSaleLeaseback" abstract="false" name="ProceedsFromFailedSaleLeaseback" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_ProductsMember" abstract="true" name="ProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentRecognizedIdentifiableAssetsAcquiredGoodwillandLiabilitiesAssumedNet" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentRecognizedIdentifiableAssetsAcquiredGoodwillandLiabilitiesAssumedNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_ProvisionToReturnAdjustmentRecognized" abstract="false" name="ProvisionToReturnAdjustmentRecognized" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_DisposalGroupsIncludingDiscontinuedOperationsDisclosureOfPerformanceMaterialsTextBlock" abstract="false" name="DisposalGroupsIncludingDiscontinuedOperationsDisclosureOfPerformanceMaterialsTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
<xs:element id="ecvt_EquityMethodInvestmentsChargesRelatedtoPurchaseAccounting" abstract="false" name="EquityMethodInvestmentsChargesRelatedtoPurchaseAccounting" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesCurrent" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPlanTax" abstract="false" name="AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPlanTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_IncomeTaxBenefitOnTransactionCostsAndStockBasedCompensationExpenseOnly" abstract="false" name="IncomeTaxBenefitOnTransactionCostsAndStockBasedCompensationExpenseOnly" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_DefinedBenefitPlanBenefitObligationPremiumsPaid" abstract="false" name="DefinedBenefitPlanBenefitObligationPremiumsPaid" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_BusinessCombinationsMember" abstract="true" name="BusinessCombinationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayable" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_ActuarialGainLossChangesduetoDemographicExperience" abstract="false" name="ActuarialGainLossChangesduetoDemographicExperience" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_RestrictedStockRestrictedStockUnitsRSUsandPerformanceStockUnitsPSUsMember" abstract="true" name="RestrictedStockRestrictedStockUnitsRSUsandPerformanceStockUnitsPSUsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_ForeignCurrencyAdjustmentsRelatedtoEquityMethodInvestments" abstract="false" name="ForeignCurrencyAdjustmentsRelatedtoEquityMethodInvestments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_Chem32Member" abstract="true" name="Chem32Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" abstract="false" name="DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
<xs:element id="ecvt_A2020TermLoanFacilityMember" abstract="true" name="A2020TermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_A2020MonteCarloSimulationMember" abstract="true" name="A2020MonteCarloSimulationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_January2022InterestRateCapExpiringOctober2024Member" abstract="true" name="January2022InterestRateCapExpiringOctober2024Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_SubsurfaceRemediationAndWetlandsManagementMember" abstract="true" name="SubsurfaceRemediationAndWetlandsManagementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
<xs:element id="ecvt_PrincipalPaymentsUnderFinanceLeasesAndFinancingObligationsIncludedInFinancingCashFlows" abstract="false" name="PrincipalPaymentsUnderFinanceLeasesAndFinancingObligationsIncludedInFinancingCashFlows" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_AccumulatedDefinedBenefitPlansAdjustmentSettlementGain" abstract="false" name="AccumulatedDefinedBenefitPlansAdjustmentSettlementGain" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_EquityMethodInvestmentAmortizationExpense" abstract="false" name="EquityMethodInvestmentAmortizationExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_DefinedBenefitPlanPlanAssetsPremiumsPaid" abstract="false" name="DefinedBenefitPlanPlanAssetsPremiumsPaid" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
<xs:element id="ecvt_PermitsMember" abstract="true" name="PermitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>


8 Subsequent Filings that Reference this Filing

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 2/29/24  Ecovyst Inc.                      10-K       12/31/23  167:20M
 3/06/23  Ecovyst Inc.                      424B7                  2:389K                                   Donnelley … Solutions/FA
 3/02/23  Ecovyst Inc.                      424B7                  1:359K                                   Donnelley … Solutions/FA
 2/28/23  Ecovyst Inc.                      10-K       12/31/22  185:28M
11/15/22  Ecovyst Inc.                      424B7                  2:576K                                   Donnelley … Solutions/FA
11/14/22  Ecovyst Inc.                      424B7                  1:542K                                   Donnelley … Solutions/FA
 8/04/22  Ecovyst Inc.                      424B7                  2:444K                                   Donnelley … Solutions/FA
 8/03/22  Ecovyst Inc.                      424B7                  1:408K                                   Donnelley … Solutions/FA


23 Previous Filings that this Filing References

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 1/14/22  Ecovyst Inc.                      S-8         1/14/22    5:168K                                   Donnelley … Solutions/FA
11/09/21  Ecovyst Inc.                      10-Q        9/30/21  106:12M
 8/09/21  Ecovyst Inc.                      10-Q        6/30/21  104:12M
 8/03/21  Ecovyst Inc.                      8-K:1,2,5,8 8/01/21   12:265K                                   Donnelley … Solutions/FA
 7/15/21  Ecovyst Inc.                      8-K:1,9     7/12/21   11:212K                                   Donnelley … Solutions/FA
 6/30/21  Ecovyst Inc.                      8-K:1,9     6/24/21   11:149K                                   Donnelley … Solutions/FA
 6/11/21  Ecovyst Inc.                      8-K:1,2,9   6/09/21   12:5.8M                                   Donnelley … Solutions/FA
 3/23/21  Ecovyst Inc.                      8-K:5,7,9   3/22/21   12:203K                                   Donnelley … Solutions/FA
 3/04/21  Ecovyst Inc.                      8-K:1,7,8,9 2/28/21   12:978K                                   Donnelley … Solutions/FA
12/18/20  Ecovyst Inc.                      8-K:2,5,8,912/14/20   14:519K
10/16/20  Ecovyst Inc.                      8-K:1,8,9  10/15/20   12:911K                                   Donnelley … Solutions/FA
 2/27/20  Ecovyst Inc.                      10-K       12/31/19  182:30M
12/03/19  Ecovyst Inc.                      8-K:5,9    11/26/19   12:224K                                   Donnelley … Solutions/FA
11/21/19  Ecovyst Inc.                      8-K:5,9    11/15/19   11:198K                                   Donnelley … Solutions/FA
 5/10/19  Ecovyst Inc.                      10-Q        3/31/19  101:9.5M
12/26/18  Ecovyst Inc.                      8-K:5,9    12/21/18    2:46K                                    Donnelley … Solutions/FA
 8/09/18  Ecovyst Inc.                      8-K:5,7,9   8/06/18    4:161K                                   Donnelley … Solutions/FA
12/13/17  Ecovyst Inc.                      8-K:1,2,9  12/11/17    2:929K                                   Donnelley … Solutions/FA
11/14/17  Ecovyst Inc.                      10-Q        9/30/17   92:9.3M
 9/19/17  Ecovyst Inc.                      S-1/A¶                15:9M                                     Donnelley … Solutions/FA
 9/01/17  Ecovyst Inc.                      S-1/A¶                15:9M                                     Donnelley … Solutions/FA
 8/14/17  Ecovyst Inc.                      S-1/A¶                12:9.2M                                   Donnelley … Solutions/FA
 6/09/17  Ecovyst Inc.                      S-1                   16:14M                                    Donnelley … Solutions/FA
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