U G .JOHNSON
14
Vol. 68
It is illustrated below in the preparation of 4- and benzene was then resumed, pieldins 8 g. of material. nitro-2,4,6-trimethy1-2,~~~~. b. p. 80-115' and 77 g. at 119' Ot t h ~ N-(%mi~& Method B. Preparation of 4-Nitca-2,4,6-trhethy1-2,6- batyl)-dimethylamiie. The residue was 5 g., coavasion diuzaheptane from 2-Nitr0-2-methy1-1,3- ro d o l and 66.5%. Dimethylamine.--A mixture of 351 g. of a % . g d m e t h y l The conversion t o pure polyamines, on the basis of the amine solution (2 moles) and 135 g. of 2-nitro-2-methyl- nitropadlim, was the same whether the pure nitro amines 1,3-proponediol (1 mole) was placed in a quart bottle and oc the crude nitro amines were hydrogenated. left in the refrigerator overnight. A reaction took place Acknowledgment.-The author wishes to at once and a non-aqueous layer separated. This layer solidiied on cooling, weight 138.4 g. It liquefied at room thank Dr. J. A. Riddick, Dr. P. C. Markunaa pounds.
temperature and was dned over anhydrous sodium sulfate. Crude conversion was 72%. Attempted distillation of a portion of the product resulted in decomposition; m. p. of crystals, 32.0'. The remainder of the material was reduced and identified as the amine.
III. Hydrogenation of Nitro Amines to Polyamines1 The various nitro amines that were prepared were in turn hydrogenated to the corresponding polyamines. The method of reduction is illustrated in the following example: One mole (148 g.) of N-(2nitroisobutyI)dimethylamine was dissolved in 500 ml. of methanol and 8 g. of Raney nickel catalyst added. The reduction was carried out at 30-50' under 600 lb. sq. in. of hydrogen. The complete ness of the reduction may be followed by the absorption of hydrogen. The solution was liltered on removal kom the bomb. The filtrate was distilled a t room temperature to remove methanol. When nearly all the alcohol was removed, the distillation was stopped and 200 ml. of benzene added. A Dean and Stark moisture trap' was connected to the column and the mixture refiuxed to remove water. (A binary constant boiling mixture of methanol and benzene distilled first.) Distillation of the residual product (2) It is pointed out that hydrogenation of nitro amines to polyaminu ihoutd not be started at high temperatures since a violent reaction may take place because of the exothermic t l p m e of the hydrogenation process. (3) Dean and Struk, Xnd. &ne. Ckm., I),486 (1920).
[CONTRIBUTION FROM
and associates for the analyses reported in this work. SummnrP The reaction of secondary aliphatic amines with formaldehyde and both primary and secoflc1ary nitropardfins has been demonstrated. Two methods have been used to prepare the nitro amines either of which gives the same end-prodnct, e. g., the amine plus formaldehyde when treated with the nitroparafiin gives the nitro amine or the amine may be added directly to the nitro alcohol (or diol) to give the nitro amine. The reactions are illustrated as follows RiNH
+ CHiO + (CH8)rCHNa +
RiNCHiC(CHdiN0:
PRtNH
+ CHaC(NOz)(CHiOH)i+
W' I
RrNHG4-CHiNRs
I
+ Ha0 + 2HiO
Not
The nitro amines were reduced to the corresponding polyamines using Raney nickel catalyst. TEaaB am,INDIANA RBCE~BO AUGUST23,1985
RESEARCH A N D DEVELOPMENT DEPABTMBNT, COHXERCUL SoLVENTS CORFQRATION]
The Preparation and Reduction of Nitro Amines Obtained from Aromatic Amines, Formaldehyde, and Nitropara5s* BY HALG.JOIw!"t Duden, Bock and Reid' have shown that 2nitro-l,&bisanilinopropane can be prepared by the action of aniline on the reaction product of dimethylamine, formaldehyde and nitromethane. (According to our nomenclature the compound above would be N,N'-diphenyl-2-nitro-l,&propanediamine.)l It is to be noted, however, that the reaction is one of substitution
prepared by the reaction of nitroolefins with amines. H
o
r
n
l
+ CH,==C"Ch
+
H ~ N H C H ~ C H ~ N O ,
All of the compounds prepared by this method must of necessity have at least one hydrogen atom alpha to the nitro group, i. e., it is impossible (CHs)zNCHlCH(NOs)CHzN(CHa)i 2CcHsNH1+ to prepare a compound having both alpha hydro(~ N H C H , ) , C H N O ~ ~ ( C W ~ N Hgen atoms substituted. Cerf* stated that nitropardfins of the type Dickey* has also shown the preparation of a number of compounds related in structure to RCHzNOa react with one mQle of N-hydroxythose discussed in this paper. His compounds are methyldi~lamine. He was not successful in treating two moles, as did Henry14JMousset' and * Prepared for the 1945 Meeting-in-Print of the Divisionof Organic Senkus,' all of whom obtained products of the type Chemistry, American Chemical Society.
+
+
t Presently asstdated with the Dykern Company, St. Louis, Missouri. (1) Duden, Bock and Reid, Be.,88, 2036 (1905). (2) J. B. Dickey, U. S. Patent 2,292,212. October 5, 1939, "Amino Compound."
(3) Cerf, B d . roc. chim., [51 4, l4Sl (1931); 151 4, 1460 (1931). (4) Henry, Be?., 88,2027 (1906). (6) Henry, Bull. wad. roy. m d . Belgique, 131 Sa, 412 (1897). (6) Moussct, ibid., 622 (1901). (7) M.Senkus, THISJOURNAL. 68, 10 (1946).
Jan., 1946
PBspanaTIo~AND
REDUCTIONOF N m o hums
R’
RNH: RNHCHsOH
R-NHcH+-cH*NHR
+ CH:O
+ H--C(R):NOI
-
NG
15 (1)
R ” P H
(2)
RNEICH:C(R):NG
When nitro alcohols sire used (Methad B) the first
where R is alkyl or aralkyl, and R‘ is alkyl or step is hydrogen. seakus hasdiscussed in greater detail OHItC(N4)CHSOH H--CILNOI CHsO (1) the limitations of the reaction as studied by Cerf, Henry and Mousset. In view of the successful followed by the reaction of the amine with the extension of the reaction by Senkus7and Johnson* formaldehyde. The formation of nitro hydroxy it was a natural outgrowth to include aromatic compounds is a reversible reaction lls128uy carried amines in the study. However, aromatic amines out in the presence of calaum hydroxide which behaved dif€mtly. When the reaction was tried prevents the reversal of the &on. Actually in the usual manner there was no evidence of a re- the reaction of N-hydroxymethylamines with action. It was decided that possibly the low nitroparafhs is similar to the Maunich reaction ionization constant of aniline might be a factor. where the active hydrogen is furnished by the Subsequently this concept proved coned as the aldehyde or ketone rather than the nitroparafk~ d o n did take place in the presence of a CH:O 4- (G&)fiNH + strongly basic catalyst. Even then some aro- G&COCHa ~ C O c I t C ” ( ~ ) ; E40 matic amines apparently have such a low ionizaBy analogy both a-picoline and quinaldine were tion constant that the catalyst IS ineffective. For example, no reaction could be obtained with di- tried unsuccessfully as sources of active hydrogen phenylamine or 1- atid 2-amino~t.hraquinones atoms for reaction with N-hydroxymethylamines. The nitro amines described herein were hydrounder any conditions tried and with p-nitroaniline it was exceedingly diilidt to get a re- genated to the corresponding polyamines and their properties and method of reduction are reported action. It has been found that aromatic amines can here also. It is of intwest that the color of the n i b react with formaldehyde and either primary or secondary nitroto yield products of the derivatives is a function of the substituents present in the aromatic ring. The color of each comfollowing general structure pound is listed in Table I and it is readily seen that ArNH: C&O RsCHNQ + the chloro, sulfonic acid and carboqlic acid R derivatives are white whereas the alkyl derivaI tives are yellow. It was also noted that the posiArNHCH;C-NQ Ha0 (1) tion of the group in the ring makes a Merence in I R the color intensity. These phenomena might be where Ar represents an aryl group such as phenyl, explained in the light of Robhson’ss theory of naphthyl, diphenyl or substituted aryl groups, electronic organic chemistry. The meta position is not conjugated with the ring and does not exert and R represents an alkyl p u p the same electronic effect as do substituents in 2 h N H : + 2 C W + RcH:NQ + the ortho and para positions.
+
+
+
+
+
+
i
ArNHCH: C H : W
I
(2)
NO¶
where A r is an aryl or substituted aryl group, and R is an alkyl group; and diamines give NHrAr-NH: R
+ 2CH10 + 2R&HNOa +
I NQ
