Table Of ContentThe Pennsylvania State College
The Graduate School
Department of Chemistry
SYNTHESIS AND PROPERTIES OF TRIMETHYLHYDRAZINE AND
TETRAMETHYLHYDRAZINE
A Dissertation
by
Jay Bernard Class
Submitted in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy
June 1952
Approved;
MAY 29 1952
TABLE OF CONTENTS
Introduction 1
Historical 2
Discussion n
The Preparation and Properties of Tri- and
Tetrame thylhydraz ine U
The Reaction of Trimetbylhydrazine-Metal Complex
with Methyl Iodide 19
Experimental 23
N, N-Dimethylhydrazine 23
Preparation of Nitrosodimethylamine 23
Preparation of N,N-Dimethylhydrazine 23
Ifethylenedimethylhydrazine 25
Trimethylhydrazine 28
Preparation 28
Reaction with Phenyl Isothiocyanate 31
Reaction of Trimethylhydrazine-Metal Complex with
Methyl Iodide 32
The Reaction 32
Analysis of the Hydrochloride Mixture 33
N, N' -Dif ormylhydr azine 35
N^N'-Diformyl-Nj N-Dimethylhydrazine 36
Tetramethylhydrazine 37
Physical Measurements 39
Boiling Point 39
Melting Point 39
Refractive Index oh/334;S ^9
TABLE OF CONTENTS (continued)
Density 39
Molar Refraction 40
Dielectric Constant 4-0
Equivalent Weight and Basic Dissociation Constant 40
Cryoscopic Molecular Weight in Via ter 41
Vapor Density Molecular Weight 41
Summary 42
Bibliography 43
INDEX OF TABLES
1. Summary of Tri- and Tetraalkylhydrazines 10
2. Physical Properties of Trimethylhydrazine 14
3. Physical Properties of Tetramethylhydrazine 15
4* Physical Properties of Methylenedimethylbydrazine 16
5. Boiling Point Comparison of Hydrazines ■with Analogous
Hydrocarbons 18
6. Boiling Point Comparison of Amines with Analogous
Hydrocarbons 18
7* Melting Point Comparison of Hydrazines with Analogous
Hydrocarbons 20
8. Melting Point Comparison of Amines with Analogous
Hydrocarbons 20
9* Summary of the Preparations of Nitrosodimethylamine 24
10. Summary of the Preparations of Methylenedimethylhydrazime 29
11. Summary of the Preparations of Trimethylhydrazine 31
ACKNOWLEDGMENT
The author wishes to express his sincere
gratitude to Dr. John. G. Aston, director of this research,
for his constant encouragement and enthusiasm.
To Dr. Thomas S. Oakwood for his helpful aid and
advice in bringing this work to a successful conclusion,
the author is also Indebted.
For their financial support, the author would
like to thank the Office of Naval Research and the Allied
Chemical and Dye Corporation.
1
INTRODUCTION
The nitrogen-nitrogsn single bond can occur in a side
variety of organic compounds. Despite the fact that hydrazine deriva
tives of acids, carbonyl groups, and variously substituted hydrocarbon
radicals are veil known to chemists today, investigation of the hydra
zine bond in organic molecules has not been very thorough. This is
due mainly to the difficulty in obtaining the simple alkyl substituted
compounds of hydrazine. Especially suitable for scientific study are
the methyl derivatives, since their structural simplicity makes them
more readily subject to theoretical treatment. The object of this
thesis, therefore, was the preparation of the two previously unknown
compounds, trimethylhydrazine and tetramethylhydrazine. - This has been
successfully accomplished. It is hoped that the methods employed in
the synthesis of these two basic moleouleB will be of aid to future
workers in making other alkylhydrazines available for scientific study.
HISTORICAL
Die first attempt to prepare a tri- or tetraalkylhydrazine
was reported in the literature only eleven years after Theodor Curtlus
in 1887 had announced the successful synthesis of hydrazine itself,"^
C. Harries was interested in the reaction of methyl iodide on hydrazine
2
hydrate as described by von Rothenberg, A strong exothermic reaction
resulted, von Rothenberg reported, which produced an e thylene-like odor.
He was able to isolate only hydrazine dihydroiodide, NgH^SHI, as one
of the reaction products, Harries saw no reason why hydrazine should
not be successively methylated by methyl iodide and set out to investi-
3
gate further. He expected Mat least six products, such as methylhy-
drasine, two dimethylhydrazines, trimethylhydrazine, trimethyl- and
hexametbylhydrazonium iodide,” but found the reaction proceeded almost
quantitatively to trimethylhydrazonium iodide, A stepwise methylation
of only one of the amino groups was suggested by Harries to explain this
fact.
In 1941 an extensive paper entitled ttThe Preparation of Tri-
4
and Tetraalkylhydrazines" was published by F. Klages and co-workers.
The problem was investigated thoroughly and Klages reported the first
preparations of these compounds. Three methods of attack were used,
coupling of dialkylnitrogen radicals, decomposition of hydrazonium bases,
and alkylation.
Die radical coupling attempts failed completely. Die reaction
between dimethylohloramine and powdered copper-bronze, a Wurtz-type
reaction, proceeded as follows:
3
Ciyj&g.HCl 31 g.
(CH3)2NH-HC1 37 g.
ch3
y NCI + Cu-bronze ether
/ ^ ch3 ch3
ch3
^NCHjN ^ 16 g.
102 g. 135 g. CB3 CH
3
CHq
I ■/
/ " \
°fc
N N 10 g.
. \ / \
ch3 ch2 ch3
The possibility' that a metal-nitrogen compound would produce
the desired results was investigated. The reaction is represented by
the equation below.
(ch3)2nh*hci 30 g.
ch3 ch3
\ imi . \ „ dioxane
/ NG1 ^ C^myHCl 5 g.
CH3 CH3 CH3 CH3
28 g. ^>NCH2N<^
CH3 CH3 2.2 g.
The formation of formaldehyde condensation products in both
instances was explained by disproportionation of the radicals. To
eliminate this possibility di-t~butylchloramine was used in the cou
pling reaction with copper-bronze. This time neither hydrazine nor
u
disproportionstion products resulted. Klages explained this with the
equations:
HgNGl + 2 Cu ^ RgNCu + CuCl
RgNCu + H+ _________^ RgNH + Cu+
It was thought that the thermal decomposition of hydrazonium
bases would proceed in a manner similar to the decomposition of quater
nary ammonium bases, and thus yield tri- and tetrasubstituted hydrazines.
Klages investigated this attack thoroughly, ^ but found no evidence of
the formation of the desired products. He reported that the results of
the decompositions were very erratic.
Die alkylations attempted can be divided into four groups:
reduction of the condensation products formed in the reaction between
an aldehyde or ketone and a hydrazine, alkylation of metal hydrazides,
reactions with alkylating agents, and alkylations with alkyl halides
at elevated temperatures.
First, an attempt was made corresponding to the methylation
of ammonia with formaldehyde, in which the formaldehyde acts as its
own reducing agent. Die reaction between aqueous formaldehyde and
hydrazine hydrochloride resulted only in polymerization products. To
reduce the acidity of the medium, a reaction was carried out replacing
hydrazine hydrochloride with a mixture of hydrazine hydrate and formic
add. A mixture of the three methyl amines in about 17/S yield was ob
tained, with no liquid bases boiling below 100° •
Both formaldehyde and acetaldehyde condensations with hydra
zines were investigated as possible preparations for trialkylhydrazines.
5
The divalent nature of the alkylidene group obviously prevents forma
tion of tetrasubstituted compounds. Klages prepared both methylene-
and ethylidenedimethylhydrazine by condensation of N, N-dimethylhydra-
zine eith formaldehyde and acetaldehyde respectively.
(CH3)2NNH2 + CH3CH0 ______ ^ (CH3)2NN - CHCH3 80%
(CH3)2NNH2 + HCHO ______ ^ (CH3)2NN s CH2 90%
In a glacial acetic acid-alcohol solution over platinum
black the ethylidene compound was successfully reduced to N, N-dimethyl-
N'-ethylhydrazine. Bie yield was unsatisfactory and unreproducible for
two reasons. A part of the N-N bond was always hydrogenated and some
of the hydrazone was split by the glacial acetic acid. The correspond
ing methylene compound resinified in presence of the catalyst.
By employing the Grignard reaction a much more satisfactory
preparation of N, N-dimethyl-N1 -ethylhydrazine resulted.
This hydrazine, the first trialkyl compound reported in the literature,
is described as Ha completely stable liquid, boiling undecomposed at
76-77°.M Stemming from the difficulty of preparation, the authors
obviously expected the compound to be unstable.
"Why Klages did not proceed further along this line of attack
is not explained. By varying the N, N-disubstituted hydrazine, the
carbonyl reagent, and the Grignard reagent quite a number of trialkyl
