Synthesis of ethylidene bis-formamide using formic acid
AssigneeAir Products and Chemicals, Inc.
InventorsRobert K. Pinschmidt, Jr., Andrew F. Nordquist
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Abstract
Ethylidene bis-formamide, a precursor for the monomer N-vinylformamide, is made in high yield by heating together formamide and acetaldehyde in a mol ratio of at least 3:1 and in a reaction mixture which is at least 20 weight percent formic acid. In a preferred procedure the acetaldehyde is added after the formamide has been preheated and formic acid is present. Yields of ethylidene bis-formamide of over 50%, based on the acetaldehyde, are obtained in relatively short reaction times, before loss of substantial amounts of recoverable formamide through hydrolysis.
Claims9
A process for making ethylidene bis-formamide which comprises heating and contacting formamide and acetaldehyde in a mole ratio of at least 3:1 in formic acid making up at least 1/4 by weight of the reaction mixture at a reaction temperature of at least 50.degree. C.
A process for making ethylidene bis-formamide which comprises:
- (a) preparing a reaction mixture of formamide, acetaldehyde and formic acid by:
- (i) preheating said formamide, with or without formic acid present, to a temperature between 35.degree. C. and the reaction temperature;
- (ii) mixing with said formamide an amount of formic acid sufficient to make up at least 20 weight percent of said reaction mixture;
- and
- (iii) adding an amount of acetaldehyde to the preheated formamide in the presence of formic acid sufficient to make the mole ratio of the unreacted formamide to acetaldehyde in the range of 3:1 to 10:1;
- (b) heating said reaction mixture, if necessary, to a reaction temperature in the range of 50.degree. to 120.degree. C.;
- (c) holding said reaction mixture at said reaction temperature for a time sufficient to convert at least 50 mole percent of said acetaldehyde to ethylidene bis-formamide;
- and
- (d) separating formic acid and at least part of the unreacted formamide from said ethylidene bis-formamide.
Dependencies are inferred from the claim text.