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  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice" id="iosp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumberPerformanceConditionsAttached" id="iosp_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumberPerformanceConditionsAttached" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationSharesAuthorizedUnderStockEquivalentUnitsExercisePriceRangeNumberOfExercisableOptions" id="iosp_ShareBasedCompensationSharesAuthorizedUnderStockEquivalentUnitsExercisePriceRangeNumberOfExercisableOptions" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockEquivalentUnitsFairValueDisclosure" id="iosp_StockEquivalentUnitsFairValueDisclosure" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockEquivalentUnitsMember" id="iosp_StockEquivalentUnitsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TechnologyMember" id="iosp_TechnologyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UnrecognizedTaxBenefitPolicyTextBlock" id="iosp_UnrecognizedTaxBenefitPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UnrecognizedTaxBenefitsMember" id="iosp_UnrecognizedTaxBenefitsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UnremittedEarningOfForeignSubsidiary" id="iosp_UnremittedEarningOfForeignSubsidiary" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
</schema>
