US 6,632,330 B1Granted

Process for purification of alkyl alkanoate

AssigneeDavy Process Technology Limited

InventorsStephen William Colley, Norman Harris, Colin Rathmell

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Abstract

A process for the recovery of substantially pure alkyl alkanoate, such as ethyl acetate, from an impure feedstock. The impure feedstock is contacted with a selective hydrogenation catalyst in the presence of hydrogen in a selective hydrogenation zone maintained under selective hydrogenation conditions effective for selective hydrogenation of impurities containing reactive carbonyl groups thereby to hydrogenate the impurities to the corresponding alcohols. After recovery from the selective hydrogenation zone of a selectively hydrogenated reaction product mixture including the alkyl alkanoate and the corresponding alcohols, this is distilled in one or more distillation zones so as to produce substantially pure alkyl alkanoate therefrom which is recovered.

Claims30

Dependent claims

A process for the purification of an impure feedstock comprising an alkyl alkanoate which contains not more than 12 carbon atoms, the process comprising:

(a) providing an impure feedstock containing an alkyl alkanoate which contains not more than 12 carbon atoms and at least one of an alkanol and water, said feedstock further containing at least one impurity selected from the group consisting of aldehydes and ketones which contain the same number of carbon atoms as said alkyl alkanoate;
(b) contacting said impure feedstock with a selective hydrogenation catalyst in the presence of hydrogen in a selective hydrogenation zone maintained under selective hydrogenation conditions effective for selective hydrogenation of said impurities thereby to hydrogenate said impurities to the corresponding alcohols;
(c) recovering from the selective hydrogenation zone a selectively hydrogenated reaction product mixture comprising said alkyl alkanoate, hydrogen, and said corresponding alcohols;
(d) distilling material of the selectively hydrogenated reaction product mixture in at least one distillation zone so as to produce purified alkyl alkanoate therefrom;
and
(e) recovering said purified alkyl alkanoate.

3 more elements

A process for the production of an alkyl alkanoate containing not more than 12 carbon atoms by dehydrogenation of an alkanol, the process comprising:

(i) contacting a vaporous mixture containing an alkanol and hydrogen with a dehydrogenation catalyst in a dehydrogenation zone maintained under dehydrogenation conditions effective for dehydrogenation of an alkanol to yield an alkyl alkanoate containing not more than 12 carbon atoms;
(ii) recovering from the dehydrogenation zone an intermediate reaction mixture comprising hydrogen and liquefiable products comprising said alkyl alkanoate, said alkanol, hydrogen and impurities selected from the group consisting of aldehydes and ketones which contain the same number of carbon atoms as said alkyl alkanoate;
(iii) contacting at least a portion of the liquefiable products of the intermediate reaction product mixture with a selective hydrogenation catalyst in the presence of hydrogen in a selective hydrogenation zone maintained under selective hydrogenation conditions effective for selective hydrogenation of said impurities thereby to hydrogenate said impurities to the corresponding alcohols;
(iv) recovering from the selective hydrogenation zone a selectively hydrogenated reaction product mixture comprising said alkyl alkanoate, hydrogen, and said corresponding alcohols;
(v) distilling material of the selectively hydrogenated reaction product mixture in at least one distillation zone so as to produce purified alkyl alkanoate therefrom;
and
(vi) recovering said purified alkyl alkanoate.

4 more elements

Dependencies are inferred from the claim text.