Name | Difluoroacetic anhydride |
Synonyms | DIFLUOROACETIC ANHYDRIDE Difluoroacetic anhydride 2,2-difluoroacetic anhydride DIFLUOROACETIC ACID ANHYDRIDE 2,2-Difluoro-acetic acid 1,1'-anhydride 1,1,5,5-Tetrafluoro-3-oxapentan-2,4-dione Acetic acid,2,2-difluoro-, 1,1'-anhydride 2,2-difluoroacetic acid (2,2-difluoro-1-oxoethyl) ester |
CAS | 401-67-2 |
EINECS | 200-258-5 |
InChI | InChI=1/C4H2F4O3/c5-1(6)3(9)11-4(10)2(7)8/h1-2H |
InChIKey | QNRXDQIHPGZCFB-UHFFFAOYSA-N |
Molecular Formula | C4H2F4O3 |
Molar Mass | 174.05 |
Density | 1.4 |
Boling Point | 94℃ |
Flash Point | 11℃ |
Vapor Presure | 49mmHg at 25°C |
Appearance | clear liquid |
Specific Gravity | 1.59 |
Color | Colorless to Light yellow to Light orange |
Refractive Index | 1.3410-1.3450 |
Hazard Symbols | C - Corrosive |
UN IDs | 3265 |
HS Code | 29189900 |
Hazard Class | CORROSIVE |
Packing Group | II |
Application | Difluoroacetic anhydride is mainly used as an acylation reagent in organic synthesis for the introduction of difluoroacetyl groups. Difluoroacetate is an intermediate mainly used in pesticides, medicines and fluorine-containing fine chemicals. It can also be used as a solvent in lithium battery electrolytes. |
preparation | step 1: add 482.8g(3.4mol) phosphorus pentoxide and 508.8g(5.3mol) difluoroacetic acid to a 2L four-mouth flask with condenser tube, heat the oil bath to 150 ℃, and react at this temperature for 1h. After the reaction, it was cooled to below 80 ℃ and distilled under reduced pressure to obtain 400.2g(2.3mol) difluoroacetic anhydride with 98.2% purity and 86.8% yield. Step 2: In the first step, 585.6g(6.1mol) of difluoroacetic acid is added to the residue after evaporating difluoroacetic anhydride, the oil bath is heated to 150 ℃, and the reaction is carried out at this temperature for 1h. After the reaction is over, it is cooled to below 80°C and distilled under reduced pressure to obtain 604.2g of a mixture of difluoroacetic anhydride and difluoroacetic acid. The content of difluoroacetic acid is 79.7% and the content of difluoroacetic anhydride is 19.8%. Step 3: In the second step, 480g(5.0mol) of difluoroacetic acid and 176g(5.5mol) of methanol were added to the residue of difluoroacetic acid anhydride and difluoroacetic acid, reacted at 50 ℃ for 8h, and 535.4g(4.87mol) of difluoroacetic acid methyl ester was obtained by rectification with 99.7% purity. Based on the difluoroacetic acid added in the third step, the yield was 97.4%. Step 4: 604.2g mixture with 19.8% difluoroacetic anhydride content in the second step is added to 482.8g(3.4mol) phosphorus pentoxide, heated to 150 ℃ in an oil bath, and reacted at this temperature for 1h. After the reaction, it was cooled to below 80°C and distilled under reduced pressure to obtain 492.9g(2.83mol) of difluoroacetic anhydride with a purity of 97.8%. 1094.4g(11.4mol) of difluoroacetic acid was added in the first and second steps, and 893.1g(5.13mol) of difluoroacetic anhydride was obtained in the first and fourth steps with 90.0% yield. |