Dehydration process of hydrofluorocarbon or hydrochlorofluorocarbon and production method of 1,3,3,3-tetrafluoropropene using the dehydration process
A process for dehydrating a hydrofluorocarbon or hydrochlorofluorocarbon, which can be done by simple equipment, and a continuous process of producing 1,3,3,3-tetrafluoropropene using the dehydration process. The dehydration process includes cooling the hydrofluorocarbon or hydrochlorofluorocarbon in gaseous form containing water with a heat exchanger, thereby condensing and liquefying the hydrofluorocarbon or hydrochlorofluorocarbon while freezing and solidifying the water. The 1,3,3,3-tetrafluoropropene production method includes a first step for fluorinating 1-chloro-3,3,3-trifluoropropene with hydrogen fluoride to obtain a mixture of 1,3,3,3-tetrafluoropropene, unreacted 1-chloro-3,3,3-trifluoropropene, hydrogen fluoride, hydrogen chloride and by-products, or dehydrofluorinating 1,1,1,3,3-pentafluoropropane to obtain a mixture of 1,3,3,3-tetrafluoropropene, unreacted 1,1,1,3,3-pentafluoropropane and by-products, a second step for removing acidic components, a third step for dehydrating the 1,3,3,3-tetrafluoropropene by the above dehydration process, and a fourth step for purifying the 1,3,3,3-tetrafluoropropene by distillation.
1. A dehydration process of 1,3,3,3-tetrafluoropropene, comprising:
cooling the 1,3,3,3-tetrafluoropropene in gaseous form containing at least water by an indirect heat exchanger of either double-tube type, multi-cylinder type, cylindrical coil type or cylindrical jacketed type, thereby condensing and liquefying the 1,3,3,3-tetrafluoropropene while freezing and solidifying the water onto a heat transfer surface of the indirect heat exchanger.
2. The dehydration process according to claim 1 , further comprising forming the 1,3,3,3-tetrafluoropropene in gaseous form containing at least water by fluorination of 1-chloro-3,3,3-trifluoropropene with hydrogen fluoride and then subjecting the 1,3,3,3-tetrafluoropropene to washing.
3. The dehydration process according to claim 2 , wherein the 1,3,3,3-tetrafluoropropene contains at least a cis-isomer or a trans-isomer, or a mixture of cis- and trans-isomers, of the 1-chloro-3,3,3-trifluoropropene.
4. The dehydration process according to claim 1 , further comprising forming the 1,3,3,3-tetrafluoropropene in gaseous form containing at least water by dehydrofluorination of 1,1,1,3,3-pentafluoropropane and then subjecting the 1,3,3,3-tetrafluoropropene to washing to remove impurities contained in the 1,3,3,3-tetrafluoropropene.
5. The dehydration process according to claim 4 , wherein the 1,3,3,3-tetrafluoropropene contains at least the 1,1,1,3,3-pentafluoropropane as an impurity.
6. The dehydration process according to claim 1 , wherein the 1,3,3,3-tetrafluoropropene is in the form of a cis-isomer or a trans-isomer or a mixture of cis- and trans-isomers thereof.
7. A production method of 1,3,3,3-tetrafluoropropene, comprising:
a dehydration step of dehydrating 1,3,3,3-tetrafluoropropene by the dehydration process according to claim 1 ; and
a distillation purification step of distillating and purifying the dehydrated 1,3,3,3-tetrafluoropropene containing impurities.
8. The production method according to claim 7 , further comprising:
a synthesis step for fluorinating 1-chloro-3,3,3-trifluoropropene with hydrogen fluoride to obtain a mixture of the 1,3,3,3-tetrafluoropropene, unreacted 1-chloro-3,3,3-trifluoropropene, hydrogen fluoride, hydrogen chloride and by-products; and
an acid removal step for removing the hydrogen fluoride and hydrogen chloride from the mixture.
9. The production method according to claim 8 , wherein, in the acid removal step, the hydrogen fluoride is removed by contact of the mixture obtained in the synthesis step with sulfuric acid, water or aqueous basic solution.
10. The production method according to claim 7 , further comprising:
a synthesis step for dehydrofluorinating 1,1,1,3,3-pentafluoropropane to obtain a mixture of the 1,3,3,3-tetrafluoropropene, unreacted 1,1,1,3,3-pentafluoropropane and by-products; and
an acid removal step for removing hydrogen fluoride from the mixture.
11. The production method according to claim 10 , wherein, in the acid removal step, the hydrogen fluoride is removed by contact of the mixture obtained in the synthesis step with sulfuric acid, water or aqueous basic solution.