Method for preparing cyanacetaldehyde acetals
AssigneeDynamit Nobel Aktiengesellschaft
InventorsChristoph Theis, Gudrun Fickert
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Abstract
Cyanacetaldehyde acetals, which can be substituted at the alpha carbon atom, form in a high yield and purity by the transposition of the appropriately substituted 3-alkoxy-nitriles with alcohols in the presence of basic catalysts from the group of the alcoholates of the alkali or alkaline earth metals, followed by deactivation of the catalyst. Short reaction times and high yields combined with a minimum production of byproducts are achieved by the continuous performance of the transposition in the continuous-flow reactor.
Claims17
A method of preparing cyanacetaldehyde acetals of the formula ##STR3## wherein R.sup.1 represents identical or different straight-chain or branched alkyl moieties of 1 to 20 carbon atoms, or --(CH.sub.2).sub.m --Cyc, Cyc being carbon isocyclic or mononuclear or polynuclear, carbocyclic aromatic with m=0 to 5, or one of the moieties R.sup.1 or both of the moieties R.sup.1 representing --(alkylene).sub.p --OH with p=2 to 6, and wherein R.sup.2 represents H, R.sup.1, or the moieties --(CH.sub.2).sub.m --OR.sup.3 or --(CH.sub.2).sub.m --CH(OR.sup.3).sub.2, R.sup.3 representing straight-chain or branched chain alkyl moieties of 1 to 12 carbon atoms and m and Cyc having the meanings given above, comprising the steps of:
- reacting at temperatures in the range of 50.degree. to 100.degree. C., compounds of the formula ##STR4## wherein R.sup.1 and R.sup.2 have the above meaning, with alcohols of the formula
- R.sup.1 --OH III
- wherein R.sup.1 has the same meaning, in a molar ratio of compounds of formula II to alcohols of formula III in the ranges of 1:1 to 1:10,
- in the presence of a basic catalyst of the formula
- M(OR.sup.1).sub.n IV
- wherein M is an alkali metal with n=1 or an alkaline earth metal with n=2 and R.sup.1 has the same meaning as above, and which is dissolved or suspended in the alcohol component, said catalyst concentration being maintained in the range of 0.5 to 2.5 wt.% with respect to the alcohol;
- and thereafter deactivating the catalyst with carbon dioxide or an inorganic or organic acid with the exception of sulfuric and/or acetic acid.
Dependencies are inferred from the claim text.