Before exporting a Revit project to IFC, make sure that Revit supports the desired IFC entities.
To change the mapping of Revit categories to IFC entities

Export
Options
IFC Options.To override the mapping of a category for a specific Revit family
Adding the shared parameters "IfcExportAs" and "IfcExportType" to a family will override the category settings for instances of that family. The "IfcExportAs" entity name should come from the list below, and the optional "IfcExportType" should be appropriate for the entity chosen.
The following is the list of supported IFC entities are supported. NOTE: The values below will only affect family instances, normal or in-place (e.g., you can not export a Revit wall as an IfcColumn, unless it is family-based or an in-place wall.)
IfcAnnotation
IfcBeam
IfcBuildingElementProxy
IfcBuildingStorey
IfcColumnType
IfcCovering
IfcCurtainWall
IfcDoorType
IfcFooting
IfcMemberType
IfcOpeningElement
IfcPlateType
IfcRailing
IfcRamp
IfcRoof
IfcSite
IfcSlab
IfcSpace
IfcStair
IfcTransportElementType
IfcWall
IfcReinforcingBar
IfcReinforcingMesh
IfcWindowType
IfcFurnishingElement
IfcFurnitureType
IfcSystemFurnitureElementType
IfcDistributionElement
IfcDistributionControlElement
IfcDistributionFlowElement
IfcDistributionChamberElementType
IfcEnergyConversionDevice
IfcFlowFitting
IfcFlowMovingDevice
IfcFlowSegment
IfcFlowStorageDevice
IfcFlowTerminal
IfcFlowTreatmentDevice
IfcFlowController
IfcActuatorType
IfcAlarmType
IfcControllerType
IfcFlowInstrumentType
IfcSensorType
IfcAirToAirHeatRecoveryType
IfcBoilerType
IfcChillerType
IfcCoilType
IfcCondenserType
IfcCooledBeamType
IfcCoolingTowerType
IfcElectricGeneratorType
IfcElectricMotorType
IfcEvaporativeCoolerType
IfcEvaporatorType
IfcHeatExchangerType
IfcHumidifierType
IfcMotorConnectionType
IfcSpaceHeaterType
IfcTransformerType
IfcTubeBundleType
IfcUnitaryEquipmentType
IfcAirTerminalBoxType
IfcDamperType
IfcElectricTimeControlType
IfcFlowMeterType
IfcProtectiveDeviceType
IfcSwitchingDeviceType
IfcValveType
IfcCableCarrierFittingType
IfcDuctFittingType
IfcJunctionBoxType
IfcPipeFittingType
IfcCompressorType
IfcFanType
IfcPumpType
IfcCableCarrierSegmentType
IfcCableSegmentType
IfcDuctSegmentType
IfcPipeSegmentType
IfcElectricFlowStorageDeviceType
IfcTankType
IfcDuctSilencerType
IfcFilterType
IfcAirTerminalType
IfcElectricApplianceType
IfcElectricHeaterType
IfcFireSuppressionTerminalType
IfcGasTerminalType
IfcLampType
IfcLightFixtureType
IfcOutletType
IfcSanitaryTerminalType
IfcStackTerminalType
IfcWasteTerminalType