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Non-catalytic manufacture of 1,1,3,3,3-pentafluoropropene from 1,1,1,3,3,3-hexafluoropropane

A technology for pentafluoropropene and hexafluoropropane, applied in the field of production 1, can solve problems such as blockage, reactor space/time/yield loss, catalyst deactivation and the like

Inactive Publication Date: 2008-02-27
EI DU PONT DE NEMOURS & CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] This catalytic process has many disadvantages, including catalyst preparation, start-up with fresh catalyst, catalyst deactivation, possibility of catalyst-filled reactor plugging with polymerization by-products, catalyst disposal or reactivation, and long reaction times, which lead to reactor Loss in space / time / yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Reactor A (Inconel-600 reaction surface) was used. The reactor inlet gas temperature ("Reactor inlet gas temperature" in Table 1) is the reaction temperature. The reaction temperatures of the two experiments were set at 724°C and 725°C, respectively. In Test A, the added reactants were not diluted with inert gas. In Run B, helium and reactants were fed in a 1.4:1 ratio. It can be seen that the benefit of the inert gas diluent is the increased yield, which was 80% for Run B and 71% for Run A. Test B produced a lower concentration of fluorocarbon by-products. The test results are shown in Table 1. Note that "sccm" in the table stands for "standard cubic centimeter per minute".

[0033] Table 1

[0034] Reactor conditions, feed

[0035] Reactor inlet wall temperature

Embodiment 2

[0037] Reactor A (Inconel-600 reaction surface) was used in this example investigating the effect of temperature on conversion and yield. Experiment A The reactor temperature was set at 600°C. Runs B and C were set at 699°C and 692°C, respectively. Tests A and B were diluted 4:1 with helium. Test C was undiluted. Run A (600°C) had a low conversion of 0.3%. The conversions for Runs B and C (690-700°C) were higher, but still low compared to those reported in Example 1, where the reaction temperature was 725°C and the residence time in the reaction zone was also slightly longer. Yields are reported, but this is unreliable for such low conversions. From these experiments, the dependence of conversion on temperature and residence time in the reaction zone is evident. The test results are shown in Table 2.

[0038] Table 2

[0039] Reactor conditions, feed

Embodiment 3

[0041] Reactor B (Nickel 200 reaction surface) was used. In this reactor, the reactor temperature is the gas temperature at the center of the reactor ("Reactor Center Gas Temperature" in Table 3). The reaction temperature of experiments A, B and C was 800°C, and the ratio of helium / reactant was 0:1, 1:1 and 2:1, respectively. At these higher temperatures than in Example 1 and similar reaction zone residence times, the conversion on the nickel surface was high and the yields were higher. In pyrolysis, higher temperatures generally result in lower yields because of the increased rate of undesirable side reactions producing unwanted by-products. This situation is not seen in embodiment 3, proves that the nickel reaction surface is superior to the nickel alloy reaction surface of embodiment 1. This conclusion is further supported by Experiment D, in which the reaction temperature was 850°C, diluted with 4:1 helium. The conversion rate is as high as 76.9%, and the yield is 90.5%...

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Abstract

1,1,3,3,3-Pentafluoropropene (CF3CH=CF2, HFC-1225zc) can be produced by pyrolyzing 1,1,1,3,3,3-hexafluoropropane (CF3CH2CF3, HFC-236fa) in the absence of dehydrofluorination catalyst at temperatures of from about 700 DEG C to about 1000 DEG C and total pressures of about atmosphere pressure in an empty, tubular reactor, the interior surfaces of which comprise materials of construction resistant to hydrogen fluoride.

Description

technical field [0001] The present invention relates to by from 1,1,1,3,3,3-hexafluoropropane (CF 3 CH 2 CF 3 or HFC-236fa) to produce 1,1,3,3,3-pentafluoropropene (CF 3 CH=CF 2 or HFC-1225zc) method. The invention also relates to azeotropic and azeotrope-like compositions containing hydrogen fluoride and 1,1,3,3,3-pentafluoropropene, and azeotropic distillation processes for separating said compositions. Background technique [0002] 1,1,3,3,3-Pentafluoropropene is a useful cure-site monomer when polymerized to form fluoroelastomers. US patents 6703533, 6548720, 6476281, 6369284, 6093859 and 6031141 and published Japanese patent applications JP09095459 and JP09067281, and WIPO publication WO2004018093 disclose methods in which 1,1,1,3,3,3-hexafluoropropane is 1,1,3,3,3-pentafluoropropene is formed by heating at a temperature lower than 500°C with the participation of a catalyst. These low temperature catalytic routes were chosen because it is well known that fluoroca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/25C07C21/18
CPCC01B7/196C07C17/25C07C21/18C07C17/38Y02P20/582
Inventor V·N·M·劳A·C·西弗特R·N·米勒
Owner EI DU PONT DE NEMOURS & CO