Method for continuously synthesizing trifluoroacetyl chloride and sulfuryl fluoride

Abstract

The invention relates to a method for continuously synthesizing trifluoroacetyl chloride and sulfuryl fluoride, which comprises the following process: continuously introducing sulfur trioxide and trifluorotrichloroethane (F113a) into a reaction rectifying tower containing a catalyst and a filler thorough the lower part in the tower according to a mol ratio of 1:1, wherein the temperature of the tower is controlled to range between 120 DEG C and 130 DEG C, and the reflux ratio at the top of the tower is 2.5-3; introducing tower bottoms into a sulfuryl chloride separating tower for rectification and separation, wherein the tower temperature is 145-150 DEG C, and the reflux ratio is 0.5-1.0; returning pyrosulfuryl chloride in the separating tower to the middle upper part of the reaction rectifying tower, heating the sulfuryl chloride rectified off from the top of the tower to 150 DEG C, and then introducing the rectified sulfuryl chloride and preheated recycled and newly-added hydrogen fluoride gas into a reactor containing a palladium / charcoal catalyst, wherein the reaction temperature is controlled to range between 150 DEG C and 160 DEG C; separating out unreacted hydrogen fluoride from the reaction product through a cold trap, and returning to the reactor for further use; and then absorbing and separating hydrogen chloride through a falling film, drying, compressing, and condensing to obtain the sulfuryl fluoride. The invention has the advantage of easy acquisition of raw materials, and the sulfuryl chloride byproduct can be directly used for the synthesis of sulfuryl fluoride.

Description

technical field [0001] The invention relates to a method for continuously synthesizing trifluoroacetyl chloride and sulfuryl fluoride. Background technique [0002] Trifluoroacetyl chloride (CF 3 COCl) contains highly reactive acid chloride groups, which can react with many types of compounds to generate trifluoroacetic acid derivatives, and is an important fine chemical intermediate. Sulfuryl fluoride (SO 2 f 2 ) is also an important class of fine chemical intermediates, which can be used to synthesize perfluorinated compounds, and it is also a class of excellent fumigants, used for insecticide and sterilization in many industries. [0003] According to literature reports, the synthetic methods of trifluoroacetyl chloride mainly contain the following categories. [0004] The first method is to synthesize trifluoroacetyl chloride by reacting trifluoroethane chloride (mainly trifluorodichloroethane, namely F123 and trifluorochloroethane, namely F133) with oxygen under cer...

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Problems solved by technology

[0020] JP56501649 uses a very complex catalytic system (composed of mercury salts, boron halides, and halogenated sulfonic acids) to catalyze F113a and SO 3 Reaction to prepare trifluoroacetyl chloride, the reaction yield is not reported, but the catalyst system components of this method are more, also did not consider the separation and utilization of sulfuryl chloride generated in the reaction process

[0021] Compared with the oxidation method, the sulfur trioxide method can be carried out at a lower reaction temperature and normal pressure, but the composition of the catalytic system is complex, and the separation and utilization of sulfuryl chloride produced in the reaction process have yet to be resolved.

[0022] The third kind of method is the method for preparing trifluoroacetyl chloride by reacting trifluoroacetic anhydride and pyridine hydrochloride or metal hydrochloride such as sodium chloride described in DE4313793. The reaction yield is not reported, but the raw material of this method higher price

[0034] US3403144 prepares sulfuryl fluoride by reacting sulfur trioxide with barium fluoride or barium hexafluorosilicon at 500-650°C. The reaction yield is not high, and the problem of separation of by-product silicon tetrafluoride is not involved. The raw material fluorine of this method is Barium chloride or barium hexafluorosilicon is also not easy to obtain

[0035] CN1259515 prepares sulfuryl fluoride from sulfur dioxide and elemental fluorine in the presence of alkali metal fluoride and hydrofluoric acid. The reaction can be carried out at a lower temperature, but the composition of the reaction product is complicated, and the reaction yield is not reported, nor does it involve by-products separation problem

[0036] Literature (Le Zhiqiang, Bo Shengmin, Wang Guangjian, Handbook of Inorganic Fine Chemicals, Chemical Industry Press (2001), 344-345) prepared sulfuryl fluoride by pyrolysis reaction using fluorosulfonic acid and anhydrous barium chloride as raw materials, The reaction temperature of this method is high, and sulfuryl fluoride is easy to decompose, resulting in complex product composition and low reaction yield.

[0037] In summary, the existing methods for synthesizing trifluoroacetyl chloride and sulfuryl fluoride are all synthesized separately, and the by-products have not been effectively separated and utilized. Therefore, the production cost is high and the three wastes are many

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