Method for reducing formation of polychlorinated aromatic compounds during oxychlorination of C1-C3 hydrocarbons
First Claim
1. An improved process for manufacturing chlorinated hydrocarbon with reduced formation of chlorobenzenes, polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), said process starting with C1 to C3 hydrocarbon reactant selected from the group consisting of methane, ethane, ethylene, acetylene, propane, propylene, methylacetylene, and halogen substituted versions thereof, said process comprising:
- contacting said reactant with oxygen or oxygenated gas and hydrogen chloride, wherein at least a portion of the hydrogen chloride to be consumed is obtained from an external source other than from recovery from the thermal cracking of the product produced in said oxychlorination process, said contacting is conducted in the presence of an oxychlorination catalyst in a heated reaction zone operating at from 150°
C. to 600°
C. wherein chlorinated hydrocarbon is recovered from the effluents of the reaction zone, the process is characterized by the fact that the hydrogen chloride is pretreated with a means for removal of the aromatic hydrocarbons.
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Abstract
An improved process is disclosed for manufacturing chlorinated hydrocarbon by way of oxychlorination which yields reduced levels of environmental toxins such as, chlorobenzenes, polychlorinated biphenyls, polychlorinated dibenzodioxins and polychlorinated dibenzofurans. The process involves fixed bed or fluid bed catalyzed oxychlorination of a hydrocarbon reactant containing from 1 to 3 carbon atoms. The oxychlorination process consists of contacting the hydrocarbon reactant with oxygen or oxygenated gas and at least a portion of externally obtained hydrogen chloride in the presence of the oxychlorination catalyst in a heated reaction zone operated at from 150° C. to 600° C. and recovering chlorinated hydrocarbon from the effluents of the reaction zone. The improvement consists of the use of at least a portion of the hydrogen chloride from an external source other than from recovery of hydrogen chloride from the thermal pyrolysis of the product from the operated oxychlorination process, wherein the external hydrogen chloride, containing aromatic hydrocarbons, is pretreated before use in the operated oxychlorination process by a means for removal of the aromatic hydrocarbons.
45 Citations
6 Claims
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1. An improved process for manufacturing chlorinated hydrocarbon with reduced formation of chlorobenzenes, polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), said process starting with C1 to C3 hydrocarbon reactant selected from the group consisting of methane, ethane, ethylene, acetylene, propane, propylene, methylacetylene, and halogen substituted versions thereof, said process comprising:
- contacting said reactant with oxygen or oxygenated gas and hydrogen chloride, wherein at least a portion of the hydrogen chloride to be consumed is obtained from an external source other than from recovery from the thermal cracking of the product produced in said oxychlorination process, said contacting is conducted in the presence of an oxychlorination catalyst in a heated reaction zone operating at from 150°
C. to 600°
C. wherein chlorinated hydrocarbon is recovered from the effluents of the reaction zone, the process is characterized by the fact that the hydrogen chloride is pretreated with a means for removal of the aromatic hydrocarbons. - View Dependent Claims (2, 3, 4, 5, 6)
- contacting said reactant with oxygen or oxygenated gas and hydrogen chloride, wherein at least a portion of the hydrogen chloride to be consumed is obtained from an external source other than from recovery from the thermal cracking of the product produced in said oxychlorination process, said contacting is conducted in the presence of an oxychlorination catalyst in a heated reaction zone operating at from 150°
Specification