Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Patent
1992-08-13
1993-08-31
Raymond, Richard L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
564 34, C07C28106
Patent
active
052411176
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a novel process for producing semicarbazide.
Semicarbazide is a compound useful as a raw material for agrochemicals, medicinals and photographic chemicals, as a reagent for identifying aldehydes and ketones and, in particular, as a raw material for the blowing agent azodicarbonamide.
BACKGROUND ART
A process known for the production of semicarbazide uses hydrazine and urea as starting materials. Another known process starts from hydrazine and a cyanate.
Since the raw material hydrazine is expensive, these processes give semicarbazide at high cost, hence are disadvantageous.
Hydrazine is produced by oxidation of ammonia. More specifically, the Raschig, organic, and hydrogen peroxide processes may be mentioned, among others. In any process, however, energy and cost are required for concentration from a dilute solution and for ketazine hydrolysis, for instance, inevitably rendering the product hydrazine expensive.
Hydrazine can also be produced by oxidation of urea. This process is known as the urea process, and the production route to semicarbazide from the thus-obtained hydrazine is as follows: O+Na.sub.2 CO.sub.3 +2NaCl+H.sub.2 O (1) +NH.sub.3 +H.sub.2 O (2)
The above equations (1) and (2) give the following equation (3): +Na.sub.2 CO.sub.3 +2NaCl+NH.sub.3 +2H.sub.2 O (3)
The urea process requires sodium hydroxide in large amounts for the production of hydrazine and allows formation of the byproduct sodium carbonate, which requires cost of treatment. Consequently, the hydrazine production cost becomes high.
For producing semicarbazide using the abovementioned urea process, sodium hydroxide and urea are required in large amounts and costs are needed also for the treatment of the byproducts sodium carbonate and ammonia. As a result, the hydrazine production still costs high.
DISCLOSURE OF THE INVENTION
Accordingly, it is an object of the present invention to provide an economically advantageous process for producing semicarbazide which can avoid the use of sodium hydroxide in large quantities, the formation of the byproduct sodium carbonate and the costs of treatment thereof.
Intensive investigations made by the present inventors in an attempt to radically remove the drawbacks of the prior art processes mentioned above have now led to a novel process for producing semicarbazide economically in good yields.
Thus the present invention provides a process for producing semicarbazide which comprises reacting the compound represented by the formula (I) ##STR2## with ammonia.
The invention further provides a process for producing semicarbazide which comprises reacting the compound represented by the formula (I) with ammonia in the presence of a chloride, hydroxide, sulfate, carbonate, acetate, salicylate, ammine complex or ethylenediamine complex of zinc or of cadmium, or a mixture of these acting as catalyst.
As distinguished from the prior art processes, the novel process according to the invention does not use hydrazine as a starting material but gives semicarbazide from the compound of the formula (I) and ammonia.
In the present invention, a compound of the formula (I) ##STR3## is used as one of the starting materials. This compound represented by the formula (I) is known per se as described in "Hydrazine--properties and application thereof" authored by Toshio YOKOTA and published by Chijin Shokan on Mar. 10, 1968, page 9, and can be named monochlorourea sodium salt. Hereinafter, the compound of the above formula (I) will be referred to as "monochlorourea sodium salt" in this specification. With respect to monochlorourea sodium salt of the formula (I), the following resonance can be mentioned, and said compound can be represented by the formula (II) ##STR4## Monochlorourea sodium salt represented by the formula (I) can be prepared in the conventional manner without any particular limitation, for example by the following process: ##STR5##
As illustrated above, monochlorourea sodium salt of the formula (I) is generally prepared using urea, sodium hydroxide a
REFERENCES:
patent: 4482738 (1984-11-01), Rothgery
patent: 4725608 (1988-02-01), Nakaguchi et al.
Hayashi Hiroyasu
Kamiya Kazusaki
Maekawa Tsukasa
Otsuka Kagaku Kabushiki Kaisha
Raymond Richard L.
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