Process for preparing 1,1-dimethyl hydrazine

#1. Field of the Invention

#This invention relates to a process for the production of 1,1-dimethyl hydrazine.

#2. Description of the Prior Art

#Into a 250 ml three neck flask equipped with a thermometer, stirrer, reflux condenser and addition funnel was charged 8.8 g. (0.1 mole) of 1,1-dimethylurea dissolved in 50 g. water. The stirred solution was cooled to 0.degree. C. and a 15.8 weight % solution of sodium hypochlorite in the amount of 47.2 g. (0.1 mole NaOCl) containing 5.9 weight % (0.07 mole) sodium hydroxide was added within 3 to 5 minutes while maintaining the temperature at 0.degree.-2.degree. C. Following the exothermic peak experienced upon completion of the hypochlorite solution addition, 5.2 g. (0.13 mole) of sodium hydroxide was added in the form of a 20% aqueous caustic solution. With continued stirring the reaction mixture was permitted to rise to about 5.degree. C. and held for 8 minutes. The reaction mixture was then split into parts and the unsymmetrical dimethyl hydrazine was recovered by distillation. In one instance, distillation was accomplished under atmospheric conditions and in the other under vacuum (21-25 mm Hg.). The distillation carried out under atmospheric conditions yielded 83.5% unsymmetrical dimethyl hydrazine; whereas, distillation under vacuum yielded 85% of product, both yield figures based on theory. The indicated yields were determined by GLC analysis.

#In this example a series of experimental runs were conducted for the purpose of illustrating the effect in terms of observed yields of certain variables such as the combining ratio of reactants, temperature during the initial reaction step, etc. The procedure was identical to that observed in Example I with respect to operative features. Other relevant data with respect to these runs and the results obtained are given in the following Table I. Reactant amounts set forth therein are given on a molar basis.

#TABLE I ______________________________________ TEMP..sup.3 Yield Run No. DMU.sup.1 NaOCL NaOH.sup.2 .degree. C % ______________________________________ 1 0.1 0.1 0.2 0 83.0 2 0.1 0.1 0.2 10 62.5 3 0.1 0.1 0.2 20 51.7 4 0.1 0.1 0.2 30 27.0 5 0.2 0.29 0.3 0-2 55.6 6 0.1 0.10 0.11 0 54.0 7 0.1 0.10 0.08 10 48.0 8 0.1 0.10 0.07 20 48.2 ______________________________________ .sup.1 DMU - 1,1-dimethylurea .sup.2 Total amount of base .sup.3 Temperature during the addition of the NaOCl