Process for preparing hydrazodicarbonamide via ketimines

Details Process for preparing hydrazodicarbonamide via ketimines Process for preparing hydrazodicarbonamide via ketimines

2001-07-16

2002-10-29

Vollano, Jean F. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Amino nitrogen containing

Reexamination Certificate

active

06472560

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a novel process for preparing hydrazodicarbonamide (“HDC”) which is, after oxidation to azodicarbonamide (“ADC”), used as a polymerization auxiliary (Ullmann's Encyclopaedia of Industrial Chemistry, Vol. A13, 185).
It is generally known that HDC is obtained from the reaction of hydrazine with urea (Ullmann's Encyclopaedia of Industrial Chemistry, Vol. A13, 185). The yields in this process are good. However, hydrazine is relatively expensive since it is prepared by chlorination of ammonia and is also classified as a hazardous substance.
It is also known that hydrazine can be obtained from the reaction of ammonia and hydrogen peroxide in the presence of ketones and catalysts. However, the yields leave something to be desired. (Ullmann's Encyclopaedia of Industrial Chemistry, Vol. A13, 182).
Furthermore, it is known that benzophenonimine can be oxidized using oxygen in the presence of catalysts to give benzophenonazine, however, which can be cleaved only with strong acids such as sulfuric acid to form hydrazinium sulfate (Catal. Rev. CR Sci. Eng., 1990, 32, 229-277). The direct reaction of this benzophenonazine with urea to form HDC is, however, not successful.
SUMMARY OF THE INVENTION
It has now been found that hydrazodicarbonamide (“HDC”) of formula (I)
can be prepared by a process comprising
(a) reacting aliphatic ketones of formula (II)
 wherein
R
1
, R
2
, and R
3
are identical or different and are each substituted or unsubstituted alkyl, and
R
4
is hydrogen, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, or
R
1
together with R
2
or R
4
form an alkylene chain,
 with ammonia under pressure to form ketimines of formula (III)
 wherein
R
1
, R
2
, R
3
and R
4
are as defined above,
(b) oxidizing the ketimines of formula (III) with oxygen in the presence of catalysts to form ketazines of formula (IV)
 wherein
R
1
, R
2
, R
3
and R
4
are as defined above, and
(c) reacting the ketazines of formula (IV) with urea and water in the presence of catalysts.


REFERENCES:
patent: 3969466 (1976-07-01), Brown et al.
patent: 3978049 (1976-08-01), Schirmann et al.
patent: 4049712 (1977-09-01), Schirmann et al.
patent: 4176135 (1979-11-01), Ohno et al.
patent: 1146233 (1969-03-01), None
CA:89:163091 ab of JP53063315 Jun. 1978.*
CA:69:26817 ab of SU201422 Oct. 1967.*
CA:81:13069 abs of Report (1972) ICT-8/72 44 pages available from Govt. Rep. Announce. (U.S.) 74(5) 57 report 1974.*
Catal. Rev.-Sci. Eng., 32(3), (month unavailable) 1990, pp. 229-277, H. Hayashi, “Hydrazine Synthesis by a Catalytic Oxidation Process”.
Ullmann's Encyclopedia of Industrial Chemistry, vol. A13 (date unavailable), pp. 179-185.

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