Process for preparing acetals and ketals
AssigneeDsm IP Assets B.V.
InventorThomas Clavey
Life of this patent
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Abstract
The present invention is concerned with a process for preparing acetals and ketals which comprises (i) reacting an aldehyde or ketone with an alcohol in the presence of a solid acid at a temperature of below −40° C., and (ii) removing water and lower aliphatic alcohol and/or sugar alcohol from the reaction product by pervaporation.
Claims14
A process for the preparation of acetals or ketals which comprises:
- (i) reacting an aldehyde or ketone with an alcohol in the presence of a solid acid at a temperature of below −40° C. to form a reaction product mixture comprising water and a lower aliphatic alcohol selected from the group consisting of methanol and ethanol, and/or sorbose, and
- (ii) removing water and the lower aliphatic alcohol and/or the sorbose from the reaction product mixture by membrane pervaporation by bringing the reaction product into contact with an organic membrane having a flux density for methanol of 2.2 to 5 kg/(hm2) under a temperature condition of about 60° C. to about 130° C. and under pressure conditions of a pressure on a retentate side of the membrane of up to 16 bar and a pressure on a permeate side of the membrane of about 1 to 500 mbar to cause traversal of an azeotropic limiting line of the reaction product mixture.
A process for recovering acetals or ketals from a reaction product mixture obtained by reacting aldehydes or ketones with alcohols in the presence of a solid acid, wherein the process comprises:
- (i) subjecting the reaction product mixture containing an acetal or ketal together with water and unreacted aldehyde or ketone and alcohol to treatment with a solid base followed by,
- (ii) subjecting the treated reaction mixture according to step (i) to membrane pervaporation by bringing the reaction product into contact with an organic membrane having a flux density for methanol of 2.2 to 5 kg/(hm2) under a temperature condition of about 60° C. to about 130° C. and under pressure conditions of a pressure on a retentate side of the membrane of up to 16 bar and a pressure on a permeate side of the membrane of about 1 to 500 mbar to cause traversal of an azeotropic limiting line of the reaction product mixture to remove water and a lower aliphatic alcohol selected from the group consisting of methanol and ethanol and/or sorbose from the reaction product mixture.
A process for recovering acetals or ketals from a reaction product mixture obtained by reacting aldehydes or ketones with alcohols in the presence of a solid acid, wherein the process comprises:
- (i) subjecting the reaction product mixture containing an acetal or ketal together with water and unreacted aldehyde or ketone and alcohol to treatment with a solid base followed by,
- (ii) subjecting the treated reaction product mixture according to step (i) to membrane pervaporation by bringing the reaction product into contact with a ceramic membrane having a flux density for methanol of 2 to 100 kg/(hm2) under a temperature condition of about 60° C. to about 130° C. and under pressure conditions of a pressure on a retentate side of the membrane of up to 16 bar and a pressure on a permeate side of the membrane of about 1 to 500 mbar to cause traversal of an azeotropic limiting line of the reaction product mixture to remove water and a lower aliphatic alcohol selected from the group consisting of methanol and ethanol and/or sorbose from the reaction product mixture.
Dependencies are inferred from the claim text.