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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001220509-07-000005.txt : 20070828
<SEC-HEADER>0001220509-07-000005.hdr.sgml : 20070828
<ACCEPTANCE-DATETIME>20070828161846
ACCESSION NUMBER:		0001220509-07-000005
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070825
FILED AS OF DATE:		20070828
DATE AS OF CHANGE:		20070828

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SIPEX CORP
		CENTRAL INDEX KEY:			0001007800
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				046135748
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		233 SOUTH HILLVIEW DRIVE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
		BUSINESS PHONE:		408-934-7500

	MAIL ADDRESS:	
		STREET 1:		233 SOUTH HILLVIEW DRIVE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ALONIM INVESTMENTS INC
		CENTRAL INDEX KEY:			0001220509
		STATE OF INCORPORATION:			A8
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33403
		FILM NUMBER:		071084164

	MAIL ADDRESS:	
		STREET 1:		1501 MCGILL COLLEGE AVENUE
		STREET 2:		26TH FLOOR
		CITY:			MONTREAL
		STATE:			A8
		ZIP:			H3A 3N9

	FORMER NAME:	
		FORMER CONFORMED NAME:	4080661 CANADA INC
		DATE OF NAME CHANGE:	20030225
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-08-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001007800</issuerCik>
        <issuerName>SIPEX CORP</issuerName>
        <issuerTradingSymbol>SIPX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001220509</rptOwnerCik>
            <rptOwnerName>ALONIM INVESTMENTS INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1501 MCGILL COLLEGE AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>26TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>MONTREAL</rptOwnerCity>
            <rptOwnerState>A8</rptOwnerState>
            <rptOwnerZipCode>H3A 3N9</rptOwnerZipCode>
            <rptOwnerStateDescription>QUEBEC, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-08-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11366383</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>through wholly owned subsidiary Rodfre Holding LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-08-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F4"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2798507</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.36</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11366383</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>through wholly owned subsidiary Rodfre Holding LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>$15 Million 5.5% convertible Senior Note due 2026</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>5.36</value>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-08-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>C</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15000000</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-05-18</value>
            </exerciseDate>
            <expirationDate>
                <value>2026-05-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2798507</value>
                    <footnoteId id="F3"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Through wholly owned subsidiary Rodfre Holding LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This deemed disposition is as a result of the Sipex Corp.-Exar Corporation merger agreement, which is effective August 25 2007 at midnight.  The Reporting Party received stock of Exar for its Sipex stock.</footnote>
        <footnote id="F2">See footnote 1.  For each share of Sipex common stock, the reporting party received 0.6679 share of Exar common stock.  Hence for 8,567,876 shares of Sipex common stock, the reporting party received 5,722,484 shares of Exar common stock.</footnote>
        <footnote id="F3">The Note states a conversion rate of 2.68.  However, as a result of the 2007 2:1 reverse stock split affecting Sipex stock, a 5.36 conversion rate was used.</footnote>
        <footnote id="F4">This acquisition is as a result of the conversion of the $15 million Convertible Senior Note due 2026 reported below.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>(s) Guy Lavergne</signatureName>
        <signatureDate>2007-08-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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