METHOD OF PREPARING DIMETHYLCETENE AND, SUBSEQUENTLY, POLYDIMETHYLCETENE FROM ISOBUTYRIC ANHYDRIDE

• Main Authors: LINEMANN, REINHARD, LE, GUILLAUME, HUB, SERGE, MARTINO-GAUCHI, GEORGES
• Format: Patent
• Language: English; French
• Published: 10.09.2004
• Edition: 7
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC CHEMISTRY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

The invention relates to a method of preparing dimethylcetene (DMK) by pyrolysis of isobutyric anhydride (ANIB), consisting in: (a) pre-heating a mixture to between 300 and 340 DEG C at atmospheric pressure, said mixture comprising between 1 and 50 % volume ANIB for between 99 and 50 % inert gas respectively; (b) bringing said mixture to a temperature of between 400 and 550 DEG C for a contact time of between 0.05 and 10 s in order to obtain a mixture of DMK, inert gas, isobutyric acid (AIB) or unreacted ANIB; and (c) cooling (condensation step) the mixture produced in step (b) in order to separate the gaseous mixture comprising the DMK from the condensed ANIB and/or AIB. La présente invention concerne un procédé de préparation de diméthylcétène (DMK) par pyrolyse de l'anhydride isobutyrique (ANIB) dans lequel : a) on préchauffe à pression atmosphérique entre 300 et 340°C un mélange comprenant 1 à 50% en volume d'ANIB pour respectivement 99 à 50% de gaz inerte, b) puis ce mélange est porté à une température comprise entre 400 et 550°C pendant un temps de contact compris entre 0,05 et 10 s pour obtenir un mélange de DMK, de gaz inerte, d'acide isobutyrique (AIB) voire d'ANIB n'ayant pas réagi, c) le mélange issu de b) est refroidi (étape de condensation) pour séparer le mélange gazeux comprenant le DMK de l'AIB et/ou de l'ANIB condensés.