Separation and recovery of 4,4'-methylene dimethyl diphenyldicarbamate
AssigneeThe Dow Chemical Company
InventorBrian G. Pope
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Abstract
A method of separating 4,4'-methylene dimethyl diphenyldicarbamate from its 2,4' and 2,2'-isomers, from methyl phenylcarbamate, from higher phenylcarbamate derivatives, and from related compounds. The mixture is washed with methanol, thereby forming a liquid phase comprising a methanol solution of predominantly 2,4'-isomer, 2,2'-isomer, diphenyldicarbamate, methyl phenylcarbamate, and higher phenylcarbamate derivatives; and a solid phase of substantially 4,4'-methylene dimethyl diphenyldicarbamate. The 2,4'-isomer and 2,2'-isomer may also be separated by using a methanol-water solution wash.
Claims17
A method for the separation of a reaction product, 4,4'-methylene dimethyl diphenyldicarbamate;
- a reactant, methyl phenylcarbamate;
- byproduct compounds, or reaction intermediates in the condensation reaction of methyl phenylcarbamate and formaldehyde;
- other methylene dialkyl diphenyldicarbamates, and other alkyl phenylcarbamates, comprising the steps of:
- (a) washing a mixture, including the methyl phenylcarbamate reactant, byproduct compounds, reaction intermediates, other methylene dialkyl diphenyldicarbamates, or other alkyl phenylcarbamates, and the 4,4'-methylene dimethyl diphenyldicarbamate product, with an alcohol having less than four carbon atoms per molecule, thereby forming a liquid phase which includes the alcohol and the compounds in the mixture which are soluble in the alcohol, and a solid phase of substantially 4,4'-methylene dimethyl diphenyldicarbamate product;
- and
- (b) separating the solid and liquid phases.
A method for the separation of reaction products, the 4,4'-isomer, 2,4'-isomer, and 2,2'-isomer of methylene dimethyl diphenyldicarbamate;
- a reactant, methyl phenylcarbamate;
- byproduct compounds, or reaction intermediates in the condensation reaction of methyl phenylcarbamate and formaldehyde;
- other methylene dialkyl diphenyldicarbamates, and other alkyl phenylcarbamates, comprising the steps of:
- (a) washing a mixture, including the methyl phenylcarbamate reactant, byproduct compounds, reaction intermediates, other methylene dialkyl diphenyldicarbamates, or other alkyl phenylcarbamates, and the 4,4'-isomer, 2,4'-isomer and 2,2'-isomer of the methylene dimethyl diphenyldicarbamate reaction products, with a solution of methanol and water, thereby forming a liquid phase which includes methanol, water, and the compounds in the mixture which are soluble in the methanol-water solution, and a solid phase of substantially 4,4'-isomer, 2,4'-isomer and 2,2'-isomer of the methylene dimethyl diphenyldicarbamate reaction product and
- (b) separating the solid and liquid phases.
Dependencies are inferred from the claim text.