US 5,393,319 AGranted

Process for producing oxamide granules

AssigneeUbe Industries, Ltd.

InventorsYukio Inaba, Tomohiko Yamamoto, Genji Koga, Hideki Noguchi, Joji Funatsu

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Abstract

Oxamide granules are produced by (A) feed-mixing ammonia to a starting material comprising 60 to 100 weight % of a diester of oxalic acid with a C.sub.1-6 aliphatic alcohol, and 0 to 40 weight % of the same aliphatic alcohol as mentioned above, to produce oxamide and the aliphatic alcohol as by-product, while controlling the aliphatic alcohol content to 5 to 40% based on the weight of the reaction mixture to provide the resultant oxamide wetted by the aliphatic alcohol; (B) granulating the wetted product while maintaining the content of the aliphatic alcohol at a level of 5 to 40% based on the weight of the wetted reaction product; (C) heat-evaporating away the aliphatic alcohol from the wetted granules; and optionally (D) re-wetting the resultant dry oxamide granules with water in an amount of 5 to 20% based on the weight of the dry oxamide granules; and (E) re-drying the re-wetted oxamide granules, to provide oxamide granules having an enhanced mechanical strength and form-stability in water.

Claims14

Dependent claims

A process for producing oxamide granules comprising the step of:

(A) feed-mixing an ammonia-containing gas to a melt of a starting material comprising 60 to 100% by weight of an oxalic acid diester of the formula (I):
##STR3## wherein R represents a lower alkyl group having 1 to 6 carbon atoms, and about 2 to 40% by weight of an aliphatic alcohol having 1 to 6 carbon atoms, to cause the oxalic acid diester to react with ammonia and produce oxamide and a by-product consisting of an aliphatic alcohol having the same alkyl group as that represented by R in the formula (I), while controlling the content of the aliphatic alcohol in the reaction mixture to a level of 5 to 40% based on the weight of the reaction mixture to provide a reaction product in the state of a wetted solid and comprising the resultant oxamide and the aliphatic alcohol;
(B) granulating the wetted reaction product into a plurality of granules, while maintaining the content of the aliphatic alcohol at a level of 5 to 40% based on the weight of the wetted reaction product;
and
(C) drying the resultant wetted oxamide granules by heat-evaporating away the aliphatic alcohol therefrom, to provide dry oxamide granules.

2 more elements

Dependencies are inferred from the claim text.