Two-step process for manufacturing 1,1-difluoroethane
AssigneeE. I. Du Pont de Nemours and Company
InventorsMario Joseph Nappa, Klaus Guenter Wuttke
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Abstract
A process is disclosed for producing 1,1-difluoroethane (CH.sub.3 CHF.sub.2 or HFC-152a) in a two-step reaction in a manner that reduces formation of high boiling materials. The first step comprises adding at least one of HCl or HF to chloroethene (CH.sub.2 .dbd.CHCl) in order to obtain at least one of 1,1-dichloroethane (CH.sub.3 CHF.sub.2) or 1-chloro-1-fluoroethane (CH.sub.3 CHClF). The second step comprises converting 1,1-dichloroethane or 1-chloro-1-fluoroethane to 1,1-difluoroethane.
Claims8
A low tar process for producing 1,1-difluoroethane comprising:
- a) reacting chloroethene with HF or HCl in a liquid phase in the presence of catalyst in a first reaction zone under conditions sufficient to form at least one of 1,1-dichloroethane and 1-chloro-1-fluoroethane;
- b) reacting said 1,1-dichloroethane and 1-chloro-1-fluoroethane with HF in a liquid phase in the presence of catalyst in a second reaction zone under conditions sufficient to form a product stream comprising 1,1-difluoroethane;
- and
- c) recovering 1,1-difluoroethane from said product stream.
A process for making 1,1-difluoroethane comprising:
- providing an agitated liquid mass comprising HF and SnCl.sub.4,
- heating the agitated liquid mass to a temperature of about 50 to 150 C. under reflux conditions at a pressure of about 50 to 400 psig,
- withdrawing at least a portion of the agitated liquid mass,
- adding chloroethene to the withdrawn liquid mass,
- converting at least a portion of the chloroethene within the withdrawn liquid mass to 1,1-difluoroethane,
- adding the withdrawn liquid mass to the agitated liquid mass;
- and,
- recovering 1,1-difluoroethane from the agitated liquid mass.
Dependencies are inferred from the claim text.