Title: Method of preparing O-methyl-isourea hydrogen sulfate and O-methyl-isourea sulfate from cyanamide

Abstract: O-Methyl-isourea hydrogen sulfate is prepared from cyanamide, methanol, and sulfuric acid in a yield of better than 90% when crystalline cyanamide is added to a mixture of sulfuric acid and methanol containing 50 - 150 parts by weight methanol per part sulfuric acid and holding the resulting composition at -10.degree. to 20.degree.C. The recovered O-methyl-isourea hydrogen sulfate is further converted to O-methyl-isourea sulfate with yields greatly exceeding 50%, and even 80%, by holding a mixture of approximately equimolar amounts of cyanamide and of the hydrogen sulfate in a liquid medium essentially consisting of methanol at 5.degree. to 40.degree.C until the O-methyl-isourea sulfate is formed and can be recovered.

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Inventors: Weiss, Stefan (Trostberg, DT)

Application Number: 533870
Filing Date: 1974-12-18
Publication_date: 1976-01-06
Assignee: Suddeutsche Kalkstickstoff-Werke AG (Trostberg, DT)
Primary Class(es): 558/8
Other Classes:
US Patent Ref:

3551489	Dec, 1970	Schaefer et al.	260/564.
3670022	Jun, 1972	Schaefer	260/564.

Other Refs:
Primary Examiner: Schwartz, Gerald A.
Assistant Examiner:
Attorney: Berman; Hans