Method for producing fluorinated organic compounds

Abstract

Disclosed is a process for producing tetrafluoropropene comprising: (a) catalytically fluorinating at least one tetrafluoropropene in a first reactor to produce HCFO-1233xf; (b) reacting said HCFO-1233xf with hydrogen fluoride in a second reactor to produce HCFC-244bb; (c) recycling at least a portion of said HCFC-244bb back to said first reactor as recycled HCFC-244bb; and (d) catalytically dehydrochlorinating said recycled HCFC-244bb in said first reactor to produce HFO-1234yf.

Description

RELATED APPLICATIONS[0001]The present application is related to and claims the priority benefit of U.S. Provisional Application No. 61 / 053,647, which was filed on May 15, 2008, and which is incorporated herein by reference.BACKGROUND OF INVENTION[0002](1) Field of Invention[0003]This invention relates to novel methods for preparing fluorinated organic compounds, and more particularly to methods of producing fluorinated olefins.[0004](2) Description of Related Art[0005]Hydrofluorocarbons (HFC's), in particular hydrofluoroalkenes such as tetrafluoropropenes (including 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf) and 1,3,3,3-tetrafluoro-1-propene (HFO-1234ze)) have been disclosed to be effective refrigerants, fire extinguishants, heat transfer media, propellants, foaming agents, blowing agents, gaseous dielectrics, sterilant carriers, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, displacement drying agents and power cycle working fluids. Unlik...

AI Technical Summary

Benefits of technology

[0011]Applicants have found a method of producing HFO-1234yf from tetrachloropropene (TCP) that involves using a single reactor or reactor system to conduct two different reaction steps contemporaneously, namely fluorination of tetrachloropropene to produce an HFCO-1233xf intermediate and dehydrochlorination of HCFC-244bb to produce HFO-1234yf. Compared to conventional three-step processes for the manufacture of HFO-1234yf from TCP via three separate reactors, the present invention reduces the unit operations and processing equipment. This results in a more economical process from an initial capital and operating cost versus conducting the 3-steps sequentially.

Problems solved by technology

Although this appears to be a relatively high-yield process, for commercial scale production the handling of hydrogen gas at high temperature raises difficult safety-related questions.

Also, the cost of producing hydrogen gas, such as building an on-site hydrogen plant, can be in many situations prohibitive.

This process is a relatively low yield process and a very large percentage of the organic starting material is converted in this process to unwanted and / or unimportant byproducts.

Images