US2660607A

US2660607A - Process of making 2-hydroxyethylhydrazine

Info

Publication number: US2660607A
Application number: US250956A
Authority: US
Inventors: Gever Gabriel; Charles J O'keefe
Original assignee: Eaton Laboratories Inc
Current assignee: Eaton Laboratories Inc
Priority date: 1951-10-11
Filing date: 1951-10-11
Publication date: 1953-11-24
Anticipated expiration: 1970-11-24

Description

Patented Nov. 24, 1953 UNITED STATES hAiTEN'i CFFEQE PROCESS OF MAKING Z-HYDROXYE'IHYL- HYDRAZINE Gabriel Gever, Oxford, and Charles J. OKecie, Norwich, N. Y., assignors to Eaton Laboratories, Inc., Norwich, N. Y., a corporation of New York No Drawing. Application October 11, 1951, Serial No. 250,956

Claims.

This invention aims to provide an improved process of 2-hydroxyethylhydrazine.

In the past, hydroxyethylhydrazine has been made from hydrazine and ethylene oxide by a process which has required operating at reduced temperatures. In the practice of that process, the reactants were well cooled (e. g., chilled to ice-salt temperatures during the period when they were added to each other) and "then placed in a sealed tube. The temperature of the reaction mixture was then permitted to rise to ordinary room temperatures and, after a period ranging from 24 to 72 hours, the reaction was deemed to be complete. There were produced in the practice of this process, in addition to the desired hydroxyethylhydrazine, substantial quantities of undesired products. This old process is not adapted to the production of hydroxyethylhydrazine on a commercial scale because of the problems encountered in cooling the reactants and difiiculty in controlling the reaction while the temperature of the reaction mixture rises to room temperature. Furthermore, yields obtained in attempting to produce hydroxyethylhydrazine on a large scale through the practice of this old process have been limited to about 36-39%.

Other expedients which have been resorted to for the production of hydroxyethylhydrazine, such as the reaction of ethylene chlorhydrin with hydrazine, yield a salt cake and involve serious diiiiculties in the handling of the reaction mixture.

We have discovered that the diiiiculties inherent in these past processes of making hydroxyethylhydrazine can be overcome, and a surprisingly high yield of Z-hydroxyethylhydrazine can be obtained, by adding ethylene oxide to hydrazine hydrate at elevated temperatures and maintaining the reactants at such temperatures until reaction has been completed. This can be done within a period which, as compared with the time required by former processes, is extremely brief.

2-hydrcxyethylhydrazine is made in accordance with our invention by heating, to a temperature within the range of about 30 C. to about 100 0., about 2 to about '7 parts of hydrazine hydrate, which may be dissolved in water, in a closed system. 1 part of ethylene oxide is gradually added to the hydrazine hydrate and the temperature of the reaction mixture is maintained within the temperature range of about 30 C. to 70 C. during such addition.

We have found that, in the practice of our invention, the reaction proceeds in satisfactory manner at a temperature within the range of about 30 C. to about 100 C. We prefer, however, to operate at a temperature of about 70 C. as a somewhat higher yield is obtained at that temperature, We also prefer, in the practice of our invention, to use a substantial excess of hydrazine hydrate over ethylene oxide. For instance, we have obtained a yield of 93% of 2-hydroxyethylhydrazine by adding 1 part of ethylene oxide to 6.3 parts of 100% hydrazine hydrate at 70 C., whereas the yield obtained by adding 1 part of ethylene oxide to 4 parts of 100% hydrazine hydrate at 70 C. was 79%.

The ethylene oxide is added to the hydrazine hydrate at such a rate that the positive pressure in the system is in the neighborhood of 20 mm. A slower rate of addition of ethylene oxide merely serves to prolong the reaction time.

The practice of our invention is illustrated by the following example:

The process is carried out in a closed system connected to a mercury trap so that positive pressures in excess of 20 mm. will be relieved. 118 grams (2 moles) of 85% hydrazine hydrate is brought to a temperature of 70 C. by immersing the reaction flask in hot water. Ethylene oxide is then run into the hydrazine hydrate through a tube having an orifice of approximately 0.5 mm. as fast as possible without causing the system to vent itself. The flask is immersed intermittently in water of to C. to maintain the reaction mixture at a temperature of to 72 C. 14 rams (0.32 mole) of ethylene oxide is absorbed in 25 minutes at which time the addition of ethylene oxide is stopped. The excess hydrazine hydrate and water is removed by distillation under reduced pressure of 25 to 30 mm. at approximately 50 to 55 C. 21 grams of 2-hydroxyethylhydrazine is then recovered from the residue by distillation at 112 to 115 C., at 5 to 6 mm. This is 86.4% of theory.

What is claimed is:

1. 'Ihe process of making 2-hydroxyethylhyabout 30 C. to about C., gradually adding 1 part of ethylene oxide to the hydrazine hydrate gfizitmaintaging the temperature of the reaction x ure W1 in said tem er Said addition. p ature range during 2. The process of making Z-hydroxyethylhydrazine, which comprises reacting ethylene oxide with hydrazine hydrate in a closed system by 3 heating about 2 to about 7 parts of hydrazine hydrate to about 70 C., gradually adding 1 part of ethylene oxide to the hydrazine hydrate, and maintaining the temperature of the reaction mixture at about 70 C. during said addition.

3. The process of making 2-hydroxyethy1hydrazine, which comprises reacting ethylene oxide with hydrazine hydrate in a closed system by heating about 7 parts of hydrazine hydrate to a temperature within the range of about 30 C. to about 100 C., gradually adding 1 part of ethylene oxide to the hydrazine hydrate, and maintaining the temperature of the reaction mixture within said temperature range during said addition.

4. The method of making 2-hydroxyethy1hydrazine, which comprises reacting ethylene oxide with hydrazine hydrate in a closed system by heating about 2 to about 7 parts of hydrazine hydrate to a temperature within the range of about 30 C. to about 100 C., adding about 1 part of ethylene oxide to the hydrazine hydrate at such a rate that a positive pressure in the neighborhood of 20 mm. is maintained in the system during the addition, and maintaining the 4 temperature of the reaction mixture within said temperature range during said addition.

5. The method of making 2-hydroxyethylhydrazine, which comprises reacting ethylene oxide with hydrazine hydrate in a closed system by heating about 8.5 parts by Weight of 85% hydrazine hydrate to about 70 C., adding 1 part by weight of ethylene oxide to the hydrazine hydrate at such a rate that a positive pressure in the neighborhood of 20 mm. is maintained within the system during the addition, and maintaining the temperature of the reaction mixture at about 70 C. to 72 C. during said addition.

GABRIEL GEVER. CHARLES J. OKEEFE.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Graenacher et a1. Mar. 13, 1945 OTHER REFERENCES Number

Claims

1. THE PROCESS OF MAKING 2-HYDROXYETHYLHYDRAZINE, WHICH COMPRISES REACTING ETHYLENE OXIDE WITH HYDRAZINE HYDRATE IN A CLOSED SYSTEM BY HEATING ABOUT 2 TO ABOUT 7 PARTS OF HYDRAZINE HYDRATE TO A TEMPERATURE WITHIN THE RANGE OF ABOUT 30* C. TO ABOUT 100 C., GRADUALLY ADDING 1 PART OF ETHYLENE OXIDE TO THE HYDRAZINE HYDRATE, AND MAINTAINING THE TEMPERATURE OF THE REACTION MIXTURE WITHIN SAID TEMPERATURE RANGE DURING SAID ADDITION.