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Method for preparing trifluoroacetic anhydride

A technology of trifluoroacetic anhydride and trifluoroacetic acid, applied in the field of preparing trifluoroacetic anhydride, can solve the problems of low yield, poor reaction state, difficult recovery or processing, etc., and achieves safe operation, cheap and easy-to-obtain raw materials, and economical high-efficiency effect

Inactive Publication Date: 2015-07-29
ZHEJIANG SCI-TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The resulting wastewater from this process is complex and difficult to recycle or treat
In addition, due to the poor reaction state of the process, the yield is generally low, often less than 70%.
In recent years, on the basis of the above method three, the domestic patent (CN101108797) has adopted measures such as the gradation feeding method of phosphorus pentoxide to avoid the above-mentioned problems, but it is also difficult to substantially improve in actual production.

Method used

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  • Method for preparing trifluoroacetic anhydride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] In a dry 500ml reaction flask, put (17.0g, 0.12mol) white solid powder phosphorus pentoxide, and 10.0g activated carbon that was previously dried at 100-130°C, and add 150ml of toluene dried over anhydrous sodium sulfate Solvent, after mixing and dispersing evenly under mechanical stirring, slowly drop (34.0g, 0.298mol) trifluoroacetic acid, and slowly raise the temperature to reflux, react for 1.5h, and distill under normal pressure to obtain the front fraction at 39-50°C 28.6g, and the obtained front fraction was rectified by a rectifying column to obtain 23.2g of a reagent-grade product at 39-40.5°C, with a yield of 74.12%. Then continue to heat up and distill to collect 143.3g of the back cut above 50°C, the collected back cut can be recycled for the next reaction, the residue after the reaction contains unreacted phosphorus pentoxide solid, drop water or phosphoric acid aqueous solution 150ml, After the reactor is cooled, the by-product phosphoric acid aqueous solu...

Embodiment 2

[0024] In a dry 500ml reaction bottle, put (34.0g, 0.24mol) white solid powder phosphorus pentoxide, and 10.0g of activated silica gel at 100-130°C in advance, and add 150ml of anhydrous calcium chloride dried Xylene (a mixed solvent of o-, m-, and p-xylene), after mixing and dispersing uniformly under mechanical stirring, slowly drip (34.0g, 0.298mol) trifluoroacetic acid, and slowly heat up to reflux, react for 2h, usually Distilled under reduced pressure to obtain 30.2 g of the front fraction at 39-50° C., and rectify the obtained front fraction through a rectification column to obtain 25.7 g of a reagent-grade product at 39-40.5° C., with a yield of 82.11%. Then continue to heat up and distill to collect 137.5 g of the back cut above 50°C, the collected back cut can be recycled for the next reaction, the residue after the reaction contains unreacted phosphorus pentoxide solid, drop water or phosphoric acid aqueous solution 300ml, After the reactor is cooled, the by-product...

Embodiment 3

[0026] In a dry 500ml reaction flask, put (102.0g, 0.72mol) white solid powder phosphorus pentoxide, and 10.0g of activated acidic alumina which was previously dried at 100-130°C, add 150ml of o-xylene solvent, after mixing and dispersing evenly under mechanical stirring, slowly drop (34.0g, 0.298mol) trifluoroacetic acid, and slowly raise the temperature to reflux, react for 2h, and distill under normal pressure to obtain a temperature of 39-50°C 28.1 g of the first cut of the obtained first cut was rectified by a rectification column to obtain 22.1 g of a reagent-grade product at 39-40.5 ° C, and the yield was: 70.60%. Then continue to heat up and distill to collect 153.3 g of the back cut above 50°C, the collected back cut can be recycled for the next reaction, the residue after the reaction contains unreacted phosphorus pentoxide solid, drop water or phosphoric acid aqueous solution 600ml, After the reactor is cooled, the by-product phosphoric acid aqueous solution is reco...

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Abstract

The invention discloses a method for preparing trifluoroacetic anhydride. A dry chemical inert solvent, white solid powdery phosphorus pentoxide and an absorbent dried and activated at the temperature of 100-130 DEG C in advance are added to a dry reaction kettle, the mixture is uniformly mixed and dispersed through mechanical stirring; trifluoroacetic acid is dropped, then the mixture is heated, subjected to reflux to have a reaction for several hours and distilled under common pressure, so that front cut fraction at the temperature of 39-50 DEG C is obtained, the obtained front cut fraction is rectified through a rectifying column, and then a reagent-grade product at the temperature of 39 DEG C-40.5 DEG C is obtained; finally, rear cut fraction higher than 50 DEG C is collected, water or a phosphoric acid aqueous solution is dropped to residues containing unreacted phosphorus pentoxide solids after the reaction, and retreatment is performed after the reaction kettle is cooled. Raw materials are cheap and easy to obtain, the solvent can be recycled, the cost is low, economic benefits are high, and the operation is standard and safe.

Description

technical field [0001] The invention relates to a method for preparing trifluoroacetic anhydride by adopting different adsorbents to alleviate the solidification of the reaction liquid during the dehydration reaction of trifluoroacetic acid. Background technique [0002] Trifluoroacetic anhydride has a wide range of reactivity and can be used as an analytical reagent, solvent, catalyst, dehydration condensation agent, protective agent for hydroxyl and amino trifluoroacetylation, etc. It is widely used in dyes, photosensitive materials, liquid crystal display materials, medicines, pesticides, etc., and has very good development and application prospects. [0003] Currently, there are mainly three synthesis methods reported at home and abroad: the first one is obtained by reacting trifluoroacetyl chloride with sodium trifluoroacetate (JP45038523, 19701205). Due to the low boiling point of trifluoroacetyl chloride (boiling point: -27°C), its preparation, storage and use are ex...

Claims

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Application Information

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IPC IPC(8): C07C53/18C07C51/56
CPCY02P20/582C07C51/56C07C53/18
Inventor 朱锦桃吴江周俊鹏仇龙
Owner ZHEJIANG SCI-TECH UNIV
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