<SEC-DOCUMENT>0000899243-23-007345.txt : 20230307
<SEC-HEADER>0000899243-23-007345.hdr.sgml : 20230307
<ACCEPTANCE-DATETIME>20230307161512
ACCESSION NUMBER:		0000899243-23-007345
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20230307
FILED AS OF DATE:		20230307
DATE AS OF CHANGE:		20230307

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital, LP
		CENTRAL INDEX KEY:			0001372939
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712772

	BUSINESS ADDRESS:	
		STREET 1:		245 PARK AVENUE
		STREET 2:		16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10167
		BUSINESS PHONE:		212 600-9600

	MAIL ADDRESS:	
		STREET 1:		245 PARK AVENUE
		STREET 2:		16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10167

	FORMER NAME:	
		FORMER CONFORMED NAME:	CCMP Capital, LLC
		DATE OF NAME CHANGE:	20060816

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Investors III, L.P.
		CENTRAL INDEX KEY:			0001569775
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712770

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LLC
		STREET 2:		245 PARK AVENUE, 16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10167
		BUSINESS PHONE:		(212) 600-9657

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LLC
		STREET 2:		245 PARK AVENUE, 16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10167

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Investors III (Employee), L.P.
		CENTRAL INDEX KEY:			0001581003
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712767

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LLC
		STREET 2:		245 PARK AVENUE, 16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10167
		BUSINESS PHONE:		(212) 600-9600

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LLC
		STREET 2:		245 PARK AVENUE, 16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10167

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital GP, LLC
		CENTRAL INDEX KEY:			0001674350
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712771

	BUSINESS ADDRESS:	
		STREET 1:		1 ROCKEFELLER PLAZA, 16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10020
		BUSINESS PHONE:		212-600-9600

	MAIL ADDRESS:	
		STREET 1:		1 ROCKEFELLER PLAZA, 16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10020

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Associates III GP, LLC
		CENTRAL INDEX KEY:			0001718029
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712769

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172
		BUSINESS PHONE:		2126009600

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Associates III, L.P.
		CENTRAL INDEX KEY:			0001718034
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712768

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172
		BUSINESS PHONE:		2126009600

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Investors III (AV-9), L.P.
		CENTRAL INDEX KEY:			0001718030
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712764

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172
		BUSINESS PHONE:		2126009600

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Investors III (AV-7), L.P.
		CENTRAL INDEX KEY:			0001718031
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712766

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172
		BUSINESS PHONE:		2126009600

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Investors III (AV-10), L.P.
		CENTRAL INDEX KEY:			0001718032
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712763

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172
		BUSINESS PHONE:		2126009600

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CCMP Capital Investors III (AV-8), L.P.
		CENTRAL INDEX KEY:			0001718033
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38221
		FILM NUMBER:		23712765

	BUSINESS ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172
		BUSINESS PHONE:		2126009600

	MAIL ADDRESS:	
		STREET 1:		C/O CCMP CAPITAL ADVISORS, LP
		STREET 2:		277 PARK AVENUE, 27TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10172

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Ecovyst Inc.
		CENTRAL INDEX KEY:			0001708035
		STANDARD INDUSTRIAL CLASSIFICATION:	CHEMICALS & ALLIED PRODUCTS [2800]
		IRS NUMBER:				813406833
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		300 LINDENWOOD DRIVE
		CITY:			MALVERN
		STATE:			PA
		ZIP:			19355
		BUSINESS PHONE:		484-617-1200

	MAIL ADDRESS:	
		STREET 1:		300 LINDENWOOD DRIVE
		CITY:			MALVERN
		STATE:			PA
		ZIP:			19355

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PQ Group Holdings Inc.
		DATE OF NAME CHANGE:	20170531
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
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<?xml version="1.0"?>
<ownershipDocument>

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        <issuerCik>0001708035</issuerCik>
        <issuerName>Ecovyst Inc.</issuerName>
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            <rptOwnerName>CCMP Capital, LP</rptOwnerName>
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            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    <reportingOwner>
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            <rptOwnerName>CCMP Capital GP, LLC</rptOwnerName>
        </reportingOwnerId>
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            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001569775</rptOwnerCik>
            <rptOwnerName>CCMP Capital Investors III, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001718029</rptOwnerCik>
            <rptOwnerName>CCMP Capital Associates III GP, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    <reportingOwner>
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            <rptOwnerCik>0001718034</rptOwnerCik>
            <rptOwnerName>CCMP Capital Associates III, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001581003</rptOwnerCik>
            <rptOwnerName>CCMP Capital Investors III (Employee), L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001718031</rptOwnerCik>
            <rptOwnerName>CCMP Capital Investors III (AV-7), L.P.</rptOwnerName>
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        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
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            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
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    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001718033</rptOwnerCik>
            <rptOwnerName>CCMP Capital Investors III (AV-8), L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
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            <isOther>0</isOther>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001718030</rptOwnerCik>
            <rptOwnerName>CCMP Capital Investors III (AV-9), L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
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            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001718032</rptOwnerCik>
            <rptOwnerName>CCMP Capital Investors III (AV-10), L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CCMP CAPITAL ADVISORS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>1 ROCKEFELLER PLAZA, 16TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
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    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5446572</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By CCMP Capital Investors III, L.P.</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>552064</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By CCMP Capital Investors III (Employee), L.P.</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1660544</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>CCMP Capital Investors III (AV-7), L.P.</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>93947</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>CCMP Capital Investors III (AV-8), L.P.</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1878125</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>CCMP Capital Investors III (AV-9), L.P.</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>123059</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>CCMP Capital Investors III (AV-10), L.P.</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1736133</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Quartz Co-Invest L.P.</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">CCMP Capital Associates III, L.P. (&quot;CCMP Capital Associates&quot;) is the general partner of each of CCMP Capital Investors III, L.P. (&quot;CCMP Capital Investors&quot;), CCMP Capital Investors III (Employee), L.P. (&quot;CCMP Employee&quot;), CCMP Capital Investors III (AV-7), L.P. (&quot;CCMP AV-7&quot;), CCMP Capital Investors III (AV-8), L.P. (&quot;CCMP AV-8&quot;), CCMP Capital Investors III (AV-9), L.P. (&quot;CCMP AV-9&quot;) and CCMP Capital Investors III (AV-10), L.P. (&quot;CCMP AV-10&quot; and, together with CCMP Capital Investors, CCMP Employee, CCMP AV-7, CCMP AV-8 and CCMP AV-9, the &quot;CCMP Capital Funds&quot;). The general partner of CCMP Capital Associates is CCMP Capital Associates III GP, LLC (&quot;CCMP Capital Associates GP&quot;).</footnote>
        <footnote id="F2">CCMP Co-Invest III A GP, LLC (&quot;CCMP Co-Invest GP&quot;) is the general partner of Quartz Co-Invest, L.P. (&quot;Quartz&quot; and, together with the CCMP Capital Funds, the &quot;CCMP Investors&quot;).</footnote>
        <footnote id="F3">CCMP Capital Associates GP and CCMP Co-Invest GP are each wholly owned by CCMP Capital, LP. The general partner of CCMP Capital, LP is CCMP Capital GP, LLC. CCMP Capital GP, LLC ultimately exercises voting and dispositive power over the shares of common stock of Ecovyst Inc. held by the CCMP Investors. As a result, each of CCMP Capital Associates, CCMP Capital Associates GP, CCMP Co-Invest GP, CCMP Capital, LP and CCMP Capital GP, LLC may be deemed to share beneficial ownership with respect to certain of the shares of common stock of Ecovyst Inc. held by the CCMP Investors. Each of the reporting persons disclaims beneficial ownership of these securities except to the extent of its pecuniary interest therein, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.</footnote>
    </footnotes>

    <remarks>Form 1 of 2.</remarks>

    <ownerSignature>
        <signatureName>CCMP CAPITAL, LP, By: CCMP Capital GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL GP, LLC, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL ASSOCIATES III, L.P., By: CCMP Capital Associates III GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL ASSOCIATES III GP, LLC, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL INVESTORS III, L.P., By: CCMP Capital Associates III, L.P., its general partner, By: CCMP Capital Associates III GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL INVESTORS III (EMPLOYEE), L.P., By: CCMP Capital Associates III, L.P., its general partner, By: CCMP Capital Associates III GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL INVESTORS III (AV-7), L.P., By: CCMP Capital Associates III, L.P., its general partner, By: CCMP Capital Associates III GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL INVESTORS III (AV-8), L.P., By: CCMP Capital Associates III, L.P., its general partner, By: CCMP Capital Associates III GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL INVESTORS III (AV-9), L.P., By: CCMP Capital Associates III, L.P., its general partner, By: CCMP Capital Associates III GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CCMP CAPITAL INVESTORS III (AV-10), L.P., By: CCMP Capital Associates III, L.P., its general partner, By: CCMP Capital Associates III GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner</signatureName>
        <signatureDate>2023-03-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
