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CATALYTIC ALKYLATION OF TETRALIN COMMUNICATION 9. ALKYLATION OF TETRALINWITH ALKENEFRACTIONS FROM THE CRACKING OF PARAFFINS N. I. Shuikin, N. A. Pozdnyak, and T. P. Dobrynina N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences, USSR Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2011-2014, November, 1963 Original article submitted August 8, 1962 In previous papers we have reported on the conditions required in the alkylation of tetralin with individual al- kenes [1,2]. We showed that in presence of aluminum and a little alkyl bromide at 95", alkenes react completely with tetralin with formation of monoalkyltetralins in yields of up to 80%. We have now studied the alkylation of tetralin with alkene fractions of compositions Cs-Cg, CI0-Cll, and C12, which were isolated from the product of the thermal cracking of synthetic solid paraffin. We showed that in presence of 0.04 g-atom of aluminum and 0.09 mole of heptyl bromide per mole of tetralin at 80", the yields of alkyltetralins were 52.0, 80.0, and 59.1%, respectively, based on the alkenes taken for reaction. EXPERIMENTAL The product of the thermal cracking of solid paraffin supplied by Chemical Combine No. 17 was distilled at atmospheric pressure, and we collected fractions boiling over the following ranges: I, 120-160 ~ 25~ II, 160-220 ~ 20~ III, 200-215 ~ 10%. Fraction I corresponded to Cs-C9 hydrocarbons and had nZOD1.4130 and d2~ 0.7325; frac- tion II to C10-Cll, nZ~ 1.4250 and d2~ 0.7581; and fraction III to C12, n2~ 1.4300 and dZ~ 0.7415. These fractions contained 62%, 65%, and 62% of alkenes, respectively, with the double bond mainly at the end of the chain. The alkene contents were determined l~romometrieally [3], and the position of the double bond with the aid of the Raman spectra. The alkylation was carried out by the procedure that we described earlier [2]. In each experiment we took 33 g of tetralin. As initiator of the reaction we used heptyl bromide in an amount of 0.09 mole per mole of tetralin. The effect of the molar ratio of tetralin to alkene was studied at 100 ~ in presence of 0.04 g-atom of aluminum per mole of tetralin. It was shown that a molar ratio of tetralin to alkene of 2 : 1 was optimum (Fig. 1). To determine the effect of the amount of aluminum taken on the yield of alkyltetralins we carded out experiments at 100" for 4 h at a molar ratio of tetralin to alkene of 2 : 1 (Fig. 2). As will be seen from Fig. 2, for the complete reaction of the alkenes with the tetralin 0.04 g-atom of aluminum must be used per mole of tetralin. With a smaller amount of aluminum part of the alkenes does not react and the yield of alkyltetralins is reduced. Yield, ~ 20 I 1 I I /-~/ 5~ " 3~Z Z~/ Molar ratio Fig. 1. Relation of yield of alkyltetralins to molar ratio of tetralin to alkene. 1) Alkyla- don of tetralin with Cs-C9 fraction; 2) alkyla- don of tettalin with Ct2 fraction; 3) alkyla- don of tetralin with CI0-Cn fraction. Yield, % ~0 T ! 0,/35 o,, z o, z , ~ Amt. of AT Fig. 2. Relation of yield of alkyltetralins to the amount of aluminum taken. 1) For Cs-C~ fraction; 2) for ClZ fraction; 3) for CI0-Cli fraction. 1852

Catalytic alkylation of tetralin

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CATALYTIC ALKYLATION OF TETRALIN

COMMUNICATION 9. ALKYLATION OF TETRALIN WITH ALKENE FRACTIONS FROM THE CRACKING OF PARAFFINS

N. I . S h u i k i n , N. A. P o z d n y a k , a n d T . P. D o b r y n i n a

N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences, USSR Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2011-2014, November, 1963 Original article submitted August 8, 1962

In previous papers we have reported on the conditions required in the alkylation of tetralin with individual al- kenes [1,2]. We showed that in presence of aluminum and a little alkyl bromide at 95", alkenes react completely with tetralin with formation of monoalkyltetralins in yields of up to 80%. We have now studied the alkylation of tetralin with alkene fractions of compositions Cs-Cg, CI0-Cll, and C12, which were isolated from the product of the thermal cracking of synthetic solid paraffin. We showed that in presence of 0.04 g-atom of aluminum and 0.09 mole of heptyl bromide per mole of tetralin at 80", the yields of alkyltetralins were 52.0, 80.0, and 59.1%, respectively, based on the alkenes taken for reaction.

E X P E R I M E N T A L

The product of the thermal cracking of solid paraffin supplied by Chemical Combine No. 17 was distilled at atmospheric pressure, and we collected fractions boiling over the following ranges: I, 120-160 ~ 25~ II, 160-220 ~ 20~ III, 200-215 ~ 10%. Fraction I corresponded to Cs-C9 hydrocarbons and had nZOD 1.4130 and d2~ 0.7325; frac- tion II to C10-Cll, nZ~ 1.4250 and d2~ 0.7581; and fraction III to C12, n2~ 1.4300 and dZ~ 0.7415. These fractions contained 62%, 65%, and 62% of alkenes, respectively, with the double bond mainly at the end of the chain. The alkene contents were determined l~romometrieally [3], and the position of the double bond with the aid of the Raman spectra.

The alkylation was carried out by the procedure that we described earlier [2]. In each experiment we took 33 g of tetralin. As initiator of the reaction we used heptyl bromide in an amount of 0.09 mole per mole of tetralin. The effect of the molar ratio of tetralin to alkene was studied at 100 ~ in presence of 0.04 g-a tom of aluminum per mole of tetralin. It was shown that a molar ratio of tetralin to alkene of 2 : 1 was optimum (Fig. 1). To determine the effect of the amount of aluminum taken on the yield of alkyltetralins we carded out experiments at 100" for 4 h at a molar ratio of tetralin to alkene of 2 : 1 (Fig. 2). As will be seen from Fig. 2, for the complete reaction of the alkenes with the tetralin 0.04 g-a tom of aluminum must be used per mole of tetralin. With a smaller amount of aluminum part of the alkenes does not react and the yield of alkyltetralins is reduced.

Yield, ~

20 I 1 I I

/-~/ 5 ~ " 3~Z Z~/ Molar ratio

Fig. 1. Relation of yield of alkyltetralins to molar ratio of tetralin to alkene. 1) Alkyla- don of tetralin with Cs-C9 fraction; 2) alkyla- don of tettalin with Ct2 fraction; 3) alkyla- don of tetralin with CI0-C n fraction.

Yield, %

~0

T !

0,/35 o,, z o, z , ~

Amt. of AT

Fig. 2. Relation of yield of alkyltetralins to the amount of aluminum taken. 1) For Cs-C~ fraction; 2) for ClZ fraction; 3) for CI0-Cli fraction.

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Page 2: Catalytic alkylation of tetralin

TABLE !. Results of the Alkylation of Tetralin with Cs-C 9, CI0-C n, and Clz Alkene Fractiom at Various Tem )eratures

Composition of fraction

Cs-Co Clo-C n The same

w

n

CIz

Amount of fraction, g

22 28 28 28 28 28 28 28 34

Temp. of expt., ~

80

60 80

I00

�9 150 80 80

150 80

Duration of expt., h

4 4 2

13 2 2

Yield of monoalkyltetralin,

% on alkenes

52.0 60.5 80.0

70.1

60.0

69.5

40.5

65.0

59.1

Yield of higher-boiling

fraction, g

1.5 2 3 5 8

3 15

5 1

TABLE 2.

Comp. of alkenes

( I s - - C 9

Cs -- C9

Cio -- C11

C,o -- Cn

C~2

Properties of the Alkyltetralines

tB.p. of alky1-1 t tetralins

i45--t55

t55--t95

t70--175

t75"200

t90--210

t,5t30 0,9t90

1,5tt0 0,9125

t,5065 0,9085

1,5105 0,9063

1,5030 0,9055

and Results of their Spectroscopic Analysis

9

9

11

i2

, t2,5

540

577

770

864

925

E~

~ Structure of alkyltetralim

t84

198

235

2i0

t82

/C 2 R - - c - - ( C ) 5 - - C

/c 2 R - - C - - ( C ) 5 - - C

/c 2 R--C--(C)7--C

/c 2 R--C--(C)8--C

/c 2 R--C--(C)o--C

TABLE 3. R e s i d u e

i

Alkyltetralin Fractions Isolated from the Combined

Comp. of starting fraction

B f ~ ie ld ,~ o~ �9 p. o ]total amt.

fo racti~ ' [ of residue C a t 6 m m I

C 8 - - C 9

Cio -- Cn C10 - - C11

Cio -- C11 C12 C12

210--225 210--220 220--240 240--270 215--235 235--255

t0 t5 t7 t5 t0 t5

t,5130 1,5140 1,5i75 1,5250 t,5130 t,5t60

0,9t53 0,9112 0,9230 0,9245 0,9145 0,9154

In determining the effect of reaction time on the yield of alkyltetralins we showed that when the reaction time was 13 h, alkenes reacted with tetralin even in presence of 0.02 g-atom of aluminum per mole of tetralin. Increase in the reaction t ime led to the occurrence of side processes, which was evidenced by the presence of a large amount of high-boiling fractions in the reaction products (Table 1). For the alkylation of tetralin with C8-C9, C10-Ctt, and C1z alkene fractions in presence of 0.04 g-atom of aluminum and 0.9 mole of heptyl bromide per mole of tetralin, we found the following to be the optimum conditions: temperature 80 ~ reaction time 4 h, molar ratio of tetralin to alkene = 2 : 1. Under these conditions, the respective yields of the alkyltetralins were 52.0%, 80.0%, and 59.1%, based

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Page 3: Catalytic alkylation of tetralin

on the amount of alkenes taken for reaction. The yield of alkyltetralins calculated on the amount of tetralin that reacted was about 90%. The alkenes and tetralin that did not react could be used for the next alkylation.

The structures of the alkyltetralins were determined with the aid of their infrared spectra, which were run on an IKS-12 instrument in the range 2800-3000 cm "1 and on an IKS-14 instrument in the ranges 700-900 and 1600- 200.0 cm "1. They contained bands characteristic for 6-monoalkyltetralins. For the bands at 2926 and 2956 cm -1 (unsymmettic CH valence vibrations for CH 2 and CH 3 groups, respectively), present in the 2800-3000 cm "1 region, we determined the absorption coefficients 81 and s2, from which we calculated the numbers of CH 2 and CH 3 groups in the molecules (Table 2).

From the results presented in Table 2 it will be seen that in the alkylation of tetralin with the Cs-C9 fraction mainly (up to 95%) 6-isooctyltetralins are obtained, in alkylation with the C10-C u fraction we isolated 6-isodecyl- tetralin (about 55%), and 6-isoundecyltetralin (about 45~ and in alkylation with C12 alkenes we obtained 6-iso- dodeeyltetralin (about 85%).

From the combined residues obtained in the alkylation of tetralin with each of the alkene fractions we isolated alkyttetralin fractions which, according to the infrared spectra, were mixtures of 6-mono- and 6,7-di-alkyltetralins (Table 3).

We sulfonated the monoalkyltetralins obtained. The sodium salts of the sulfonic acids gave a good stable foam, which indicates the possibility of their use as detergents.

R a m a n spectra were determined by G. K. Gaivoronskaya and infrared spectra by I. N. Lifanova, and for these services the authors express their thanks.

S U M M A R Y

In the catalytic alkylation of tetralin with Cs-Cg, C10-Cll, and C12 alkene fractions from the cracking of paraf- fins, 6-isooctyltetralins, 6-isodecyl- , and 6-isoundecyltetralins, and 6-isododecyltetralins were obtained in yields of 52.0%, 80.0%, and 59.1%, respectively, based on the amounts of alkenes contained in the original fractions.

1.

2.

3.

LITERATURE CITED

N. I. Shuikin and N. A. Pozdnyak, Izv. AN SSSR, Otd. khim. nauk, 1156 (1961). N . I . Shuikin and N. A. Pozdnyak, Izv. AN SSSR, Otd. khim. nauk, 1455 (1962). G. D. Gal'pern, Tr. Inst. nefti AN SSSR, 4, 141 (1954).

Al l a b b r e v i a t i o n s of p e r i o d i c a l s in the a b o v e b ib l iography are l e t t er -by - l e t t er transLiter-

a t i o n s o f the a b b r e v i a t i o n s as g iven in the o r ig in a l R u s s i a n journal . Some or all of this peri-

od ica l l i t era ture may wel l be a v a i l a b l e in Engl ish translation. A c o m p l e t e l i s t o f the c o v e r - t o -

c o v e r E n g l i s h t r a n s l a t i o n s appears at the back o f th i s i s s u e .

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