Catalytic addition of secondary amines to ethylene (Contribution No. 1720)

1971. Pergamon Press.

Tetrahedron Letters Co.:, pp. 429-430,

CATALYTIC

Central Research

of

numerous

ADDITION OF SECONDARY AMINES TO ETHYLENE (Contribution No. 1720)

D. R. Coulson Department, Experimental Station, E. I. du Pont de Nemours and Company, Inc., Wilmington, Delaware 19898

(Received in USA

Although

frinted i.li (Great Britain.

29 September 1970; received in UK for publication 30 December 1470)

the catalytic

.

investigations,

I

addition of amines to olefins has been the subject

no additions homogeneously

We now wish to report that various compounds

metal compounds have been reported. of rhodium or iridium effectively amines to ethylene

catalyzed by transition

catalyze the addition of secondary

(eq. 1).

R1

R2 R1\

\,/

+

CH2=CH2

r CH2CH3 12 R,R

For example, a mixture rhodium trichloride

trihydrate

= alkyl

(17 g., 200 mmole),

(0.51 g., 2 mmole),

ethylene

afforded

state of the rhodium complex appeared to be immaterial,

effective.

(65% yield)

in Table I.

In all cases, the liquid phase remained homogeneous.

using the Rh(1) complex,

Other complexes

14.6 g.

(25 ml.)

The results obtained with other amines under similar

are described

were obtained

(9 g., 300 mole),

and tetrahydrofuran

to 180.C. for 3 hr. in an 80-cc autoclave

of N-ethylpiperidine. conditions

of piperidine

iR2

--3

H

when heated

aliphatic

The initial valence

since equally good results

CL-dichlorotetraethylene-dirhodium(I).

such as Rh13-3H20,

Rh(N0 ) and IrC13'3H20 also proved to be 3 3' No reaction was noted in the absence of the metal ccmplexes.

The reaction

is apparently

very sensitive

to the nature of the amine.

The first three amines in Table I gave a wide range of yields although they are of similar basicity.

Possibly

steric effects are operating here, since yields

tend to decrease with increasing basicity

(or nucleophilicity)

much less reactive

steric bulk around the nitrogen.

However,

does appear to be a factor, since morpholine

than piperidine. 429

is

No.5

430

Table Ia PRac

% Yield of N-Ethylamine

Amine

10.73

54

Dimethylamine

10.49

4

Diethylamine

ca. 10.5

3

n-Butylethylamine

11.27

Pyrrolidine

3Sb

Morpholine

<2

8.33

Piperidine

70

11.12

'Mole ratios; Amine:Ethylene:RhC13'3H20

= 35O:lOO:l;

Temp. = 200.:

Time = 3 hr.: Solvent = tetrahydrofuran. b

Appreciable

%andbook

side reactions

of Chemistry

In preliminary with piperidine be independent

% Physics, 49th edition, p. D-87, The Chemical Rubber Co.

studies of the kinetic order of the reaction of ethylene

catalyzed by rhodium trichloride, of the piperidine

rhodium trichloride. difficulties

noted.

and first order with respect to

The order in ethylene was not established because

in accurately measuring

was also shown to be irreversible detection

concentration

the reaction rate was found to

the amount of ethylene consumed.

under the reaction conditions

of The reaction

(limit of

= 0.1% reaction).

In a remarkable be essentially

display of specificity,

homologs

of ethylene were shown to

Also, primary amines or ammonia were unreactive.

unreactive.

In

the case of ammonia and, possibly, certain primary smines, thermodynamic la considerations suggest that detectable quantities of adducts may not be formed under our reaction conditions. ACENDWLEDGMENT Helpful

SUggeStiOnS

are gratefully

from Drs. R. V. Lindsey, Jr. and Chadwick A. Tolman

acknowledged. REFERENCES

(1) (a) L. Uhlmann, Wiss. 2. Tech. Hochsch.

Chem. ieuna-Merseburq,

(b) B. Howk et al., J. Am. Chem. Sot., 12, (c) British

Patent 756,538

(d) U.S. Patent 2,750,417

(1956). (1956).

(e) E. W. Stern and 14. L. Spector, (f) U.S. Patent 3,412,158

2, 263

1899 (1954).

(1968).

Proc. Cbem. Sot., 322

(1961).

(1963).