C A T A L Y T I C A L K Y L A T I O N OF T E T R A L I N

COMMUNICATION 11. ALKYLATION OF TETRALIN

IN PRESENCE OF TITANIUM TETRACHLORIDE

(UDC 542.97)

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

N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences, USSR Translated from Izvestiya Akademi i Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 119-123, January, 1965 Original ar t ic le submitted February 21, 1963

L i f a n o v a

Ti tanium tetrachlor ide was first used as an a lkyla t ion catalyst by Stadnikov and Kashtanov [ 1] for the a lky la - t ion of benzene with benzyl chloride. Later, in presence of t i tan ium tetrachloride Kullinan [2] a lkyla ted benzene,

toluene, and anisole with a lkyl halides and C 4 and C 5 tert iary and secondary alcohols. In a lkyla t ion with a lkyl ha l - ides the yield of a lkylated compounds was 82-84%, and in a lkylat ion with alcohols it was 20-74~ In the cyc loa lky l - at ion of benzene in presence of t i tanium te t rachlor ide [3] the yield of cyclohexylbenzene was 85%. We have shown ear l ier [4, 5] that in presence of zinc chloride the a lkyla t ion of te t ra l in with alcohols goes through the stage of the formation of alkenes. As a result, in a lkylat ion with normal -cha in alcohols a lkyl tetral ins are obtained with alkyl groups having various degrees of branching.

In the present investigation we studied the aIkyla t ien of te t ra l in in presence of t i tanium tetrachloride. We sup- posed that in presence of this catalyst it would be possible to obtain alkyltetral ins without any isomerizat ion of the alkyl group. The alkylat ion was carried out with the normal -cha in primary heptyl , nonyl, and decyl alcohols and also with a mixture of C 9 secondary alcohols and with 1-nonene. It was shown that for the a lkylat ion of te t ra l in with alcohols an equimolecular amount of t i tanium tetrachtor ide is necessary. In the a lkyla t ion of te t ra l in with normal - chain alcohols we obtained hep ty l - , nonyl- , and decyl - te t ra l ins in yields of 62.5, 65.5, and 55.7% respect ively, based on the amounts of the alcohols taken for reaction. With the aid of their infrared spectra we showed that these alkyltetral ins are 6-a lkyl te t ra l ins with alkyl groups of normal and branched structure.

We consider that the atkylat ion of te t ra l in with alcohols in presence of t i tanium te t rachlor ide goes by the fol- lowing scheme. First the alcohols form alkoxytr ichlorot i taniums with t i tanium tetrachloride, as shown by Nesmeyanov and co-workers [ 8]:

ells (ell2) nCH2CH20H -~- TiC]~ -4 CHs (CH2) ~CH2CH2OTiCI3 + HCl.

When heated, the alkoxytrichloroti taniums decompose in accordance with the scheme proposed fer s -a lkoxyt r ich loro- t i taninms [ 7]:

CH3(CH2) ~CHaCHeOTiCI3-+ TiOCIe + [CH3(CHe)~CHCH~ --] -1- HCl. J

The radical formc~d reacts with te t ra l in with formation of alkyl tetral ins with a chain of normal or branched structure:

-}- [CH~ CH (CI-I2)r~ CHa] -> I

CH3

103

The alkylation of tetral in with the mixture of secondary C 9 alcohols was conducted both in presence of t i tanium

tetrachloride and in presence of zinc chloride under the previously described conditions [4, 5]. In presence of t i tan i -

um tetrachloride we obtained (Cg-atkyl)tetralins in higher yields (73~ instead of 43~ with zinc chloride). The yield

of (Cg-alkyl)tetralins in the alkylation of tetralin with 1-nonene in presence of t i tanium tetrachloride was 65.507o.

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

Alkylation of Tetral in with Primary Alcohols. This was carried out at atmospheric pressure in a flask fitted

with a mechanical stirrer. One-eighth of a mole each of t i tanium tetrachloride and the alcohol was taken. The

amounts of tetralin taken are given in Table 1. First the t i tanium tetrachloride was added to the tetralin, and then the appropriate alcohol was added. On addition of the alcohol a rise in temperature and liberation of hydrogen chlo-

ride were observed. The optimum temperature was found to be 140 ~ , i.e. the temperature at which the reaction mix-

ture thickened, and then a copious evolution of hydrogen chloride was again observed. The mixture was heated for

4 h, but the alkylation reaction was in the main complete after a period of 1 h after thickening had occurred

(see Table 1, Experiments 4, 5, and 11). The reaction mixture was decomposed with water acidified with hydrochlo- ric acid, and hydrocarbons were extracted with ether. The extract was dried, ether was driven off, andthe alkylation product >}as vacuum-dist i l led at a residual pressure of 6 mm through a column of 15-plate efficiency.

Results on the fractionation of the catalyzates from typical experiments are given in Table 2.

The compositions of the fractions were investigated with the aid of their infrared spectra, determined with an

IK-12 instrument. The spectra of the fractions coming over up to 70 ~ (6 mm) in Expt. 3 and in the range 75-140 ~

(6 mm) in Expt. 11 were determined in the region 3000-3600 cm-*. In the first case we found a band at 3336 cm'* characteristic for an atcohol group. The infrared spectrum indicated that the fraction of b.p. 75-140 ~ (6 ram) con-

tained decyl alcohol impurity. Froln the combined fractions coming over up to 70 ~ (6 ram) from the experiments with decyl alcohol we isolated a fraction of b.p. 154-158 ~ (745 ram) and nD20 1.4127, corresponding to isodecane.

The infrared spectra of this fraction and of the alkyltetralin fractions were determined over the range 2800-3000 cm-t

Absorption coefficients were determined for the bands at 2926 and 2956 cm -1, which correspond to the unsymmetri- cal stretching vibrations of CH for CH 2 and CH a groups respectively, and the numbers of CH z and CH a groups in the

molecule were calculated [8, 9]. The isodecane fraction had ~CH 2 = 432 and r = 340; this corresponds to hydro-

carbons containing about 7 CH2 groups and 3 CH a groups. Results of the analysis of the alkyltetralin fractions are given in Table 3, from which it follows that the alkyltetralin fractions consist of mixtures of the appropriate alkyltet-

ralins with chains of normal and branched structure. The infrared spectra of the alkyltetralin fractions in the ranges 600-900 and 1600-2000 cm -~ show that the alkyltetralins that we obtained were 6-alkyltetralins.

The 140-180 ~ fraction of the catalyzate from Expt. 11 was investigated with the aid of the ultraviolet spectrum,

determined with an SF-4 instrument. The ultraviolet spectrum, determined in the range 210-300 rag, indicates the

presence of compounds with a naphthalene nucleus in this fraction. Thus, it was shown that in the experiments on

atkylation with decyI alcohol in addition to the alkylation of tetralin, redistribution of hydrogen occurs: the dehy- drogenation of the tetralin nucleus, and the hydrogenation of unsaturated hydrocarbons into the corresponding paraffins.

TABLE 1.

Expt.

t 2 3 4 5

7 8 9

lO II

Alkylation of Tetralin with Primary Alcohols

Alcohol

n-I lcptyl The same

n-Nonyl The same

n- l )ccyl The same

] Molar mount Ipr~176

of tetra- lions Reaction / I tetral in: time, ~in taken, I alcohol h

t g TiC]4

l 1 1

1 1 I

,•ilkyltetra- ns obtained Temp., - ----

~ g yield, %

i6,5 33,0 49,5 16,5 16,5 16,5 3',], 0 -~9,5 33,0 49,5 49,5

t40 i40 140 l .'.)0 169 [40 140 i40 l~d) i~, l

i2,5 43,5 15,0 52,0 18,0 62,0 t3,0 4O,5 t4 ,5 48,5 18,0 54,t 21,0 65,5 17,5 5~,6 t3,0 55,7 17,1 59,4 [8,5 5.~,3

High-

boiling

{ractions,

9 ,0 6,t 5,t 5,2 5,5 5,0 4,0 5,1 6,0 7,5 7,0-

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TABLE 2. Results of the Fractionation of Catalyzates from Typical Alkylation Experiments

Yield of B.p. of fraction, ~raction, n~) Expt. Alcohol ~ (6 ram)

3

il

n-Heptyl

n-Nonyl

n-Decyl

Up to 70 70--75 75--150

159--154 t54--t60 t60--t75 175--205

Above 205

UPT~05 75--170

t70--175 175--180 180--2t0

Above 2t0 Up~9 ~

7 O - - l O 75--t40

140--180 t80--t81 181--190 t90--t97 197--2t5

Above 2t5

2,0 38,0 1,0

10,0 2,5 5,5 0,5 5,8 3,1

36,t 2,0

1t,5 6,0 0,5 7,5 4,0

t4,1 3,0 2,2 5,5 8,5 5,0 t,5 9,0

1,5023 1,5420 1,5379 t,5165 t,5163 t,5143

1,4970 t,5410 t,5354 1,5t99 1,5t00 1,5tt5

1,4290 1,5335 t,5100 t,5380 t,5087 1,5100 t,5110 t,5430

TABLE 3. Resuks of the Analysis of Alkyltetralin Fractions with the Aid of Infrared Spectra

Expt. IB'P"]~ mm) ~cH~

3

8

1t

No. of CH2 No. ofCH a groups ] ECH" groups

I t50--t54 t54--t60 t60--175 t70--t75 t75--180 t89--t8t 181--i~0 t90--197

470 595 570 647 644 730 714 825

7,7 8,t 9,0

t0,0 t0,0 t t ,2 t l ,0 t2,4

I 188 2 t52 t ,5 1t0 1 t82 2 152 t,5 200 2 152 t,5 t13 1

Alkylation of Tetralin with C 9 Secondary Alcohols. The C 9 alcohols were prepared by Bashkirov and co-workers [ 1'0] by the liquid-phase oxidation of n-nonane under pressure. They boiled in the range 80-87" (6 mm) and had d~ ~ 0. 8268 and nDa0 1.4286; hydroxyl value 386; calculated 389. As Bashkirov and co-workers showed [ 10], this mixture of alcohols contains all possible position isomers, mainly secondary. Alkylation with the secondary alcohols was carried in presence of titanium tetrachloride or zinc chloride. In each experiment we took one-eighth of a mole each of the alcohol and the titanium or zinc chloride; the amounts of tetralin taken are stated in Table 4. It will be seen from Table 4 that the optimum temperature for the alkylation of tetralin with C 9 alcohols in presence of

TABLE 4. Alkylation of Tetralin with C 9 Secondary Alcohols

Catalyst

Afn o ttnt of tetralin, g

Molar pro- portions tetralin: alcohol: catalyst

Exptl. tern p., ~

Reaction time, h

Amt. obtained

(Cg-alkyl) - [ residue tetralin t of b p

- i y iel----~,l above'iT0 o

g % (6 ram)

Zinc ch',oride The san-~e

>> >>

P >>

Titanium tetrachlo- ride

t6,5 16,5 t6,5 t6,5 33 33 33

t : t : 1 1 : 1 : 1 t : t : 1 t : t : t 2 : t : t 2 : 1 : 1 2 : 1 : t

i60 t50 150 170 160 lO0 t20

t2,0 3,i 2,5 8,0

t4,0 24,i 20,0

37,2 9,0 6,2

24,8 43,5 74,6 62,0

4,0 3,1 3,1 3,0 3,0 5,2 4,0

i05

TABLE 5. Alkylat ion of Tetral in with 1-Nonene

Amt. taken, g

tetral in 1-nonene TiCI4

% by wt.

of TiCl 4 in mix -

lure taken

Molar ratio of te t ra l in to a l - kene

. . . . . A____%"

Reaction (C9_al_ t residue temp. , kyl) t e l - yield, ~ I ~ b.p. o o~ I . labove 170

I rahn, g ](6 ram)

33 16,5 16,5 t6,5 16,5 t6,5 33

15,7 7,8 7,8 7,8

i0 ,5 t0,5 2 t ,0

3,8 3,8 3,8 3,8 3,8 5,0 3,8

7,8 15,6 i5 ,6 i5 ,6 t4,2 18,5 7,0

2 i :1

160 105 80 50

105 105 105

21,1 65,5 8,0 9,3 56,i 3,1 6 , t 37,4 3,0 3,0 18,5 3 , i

t l , t 51,0 4,0 i4 ,0 65,0 3.5

Reaction did not go

t i tanium tetrachlor ide is 100 ~ whereas in presence of zinc chloride it is 160 ~ At these temperatures with molar ratios of te t ra l in to alcohol of 2 : 1 (Cg-alkyl) te tral in was obtained in yields of 74.6 and 43.5% respectively.

Alkylation of Tetral in with 1-Nonene. 1-Nonene was prepared by the pyrolysis of nonyl aceta te by the meth- od described in one of our previous papers [ 11]. A mixture of tetral in, nonene, and t i tanium tetrachloride was stirred at a temperature between 50 and 160 ~ for four h. The exper imental resuhs are given in Table 5.

It follows from Table 5 that the yield of (Cg-alkyl)tetral ins at a given temperature depends on the amount of catalyst in the mixture. Thus, at 105 ~ with 18.5% of catalyst the yield of (Cg-alkyl) tetral ins is 65%, but with 7~ of catalyst a lkylat ion does not occur, though when the temperature is raised to 160 ~ react ion in presence of 7.8o70 of catalyst goes with a yield of 65.8% of (Cg-alkyl)tetral ins. According to the infrared spectra the (C9-alkyl)tetral ins

obtained in the alkylat ion of te t ral in w ith the secondary alcohols and with 1-nonene are 6 -(branched-C 9-alkyl)tetralins.

The secondary alcohols were kindly provided by A. N. Bashkirov's laboratory.

S U M M A R Y

1. Conditions were found for the alkylat ion of te t ra l in in presence of t i tanium tetrachloride with C7-C,0

nornlal primary alcohols, with a mixture of secondary C 9 alcohols, and with 1-nonene. The yields of the 6 - a lky l t e t - ralins formed were 58-56, %%6, and 68.5% respect ively.

2. A mechanism is suggested for the alkylat ion of te t ra l in with alcohols in presence of t i tanium tetrachloride.

L I T E R A T U R E C I T E D

1. G.L. Stadnikov and L. I. Kashtanov, Zh. russk, f iz . -khim, obshch., 60, 1117 (1928).

2. N . M . Kullinan and D. M. Loyshon, J. Chem. Soc., 1984, 2942. 8. Pajeau Roger, Compt. rend. Acad. Sci colon., 252, 8060 (1961). 4. N . I . Shuikin, N. A. Pozdnyak, and E. D. Lubuzh, Izv. AN SSSR. Otd. khim. n., 1961, 1098. 5. N . I . Shuikin and N. A. Pozdnyak, Izv. AN SSSR. Otd. khim. n., 1962, 324. 6. A .N. Nesmeyanov, R. Kh. Freidlina, and O. V. Nogina, Izv. AN SSSR. Old. khim. n., 1982, 1087. 7. G.L. Razuvaev, L. M. Babinova, and V. S. Etlis, Dokl. AN SSSR, 122, No. 4, 618 (1958). 8. Yu. P. Egorov, V. A. Shlyapochnikov, and A. D. Petrov, Zh. anali t , khimii , 1_4, 617 (1959). 9. N . I . Shuikin, V. A. Shlyapochnikov, N. A. Pozdnyak, and B. L. Lebedev, Izv. AN SSSR. Otd. khim. n., 1961,

-t66. 10. V .V. Kamzolkin, A. N. Bashkirov, M. I. Khotimskaya, M. M. Grozhan, and G. M. Ezhenkina, Neftekhimiya,

i, No. 2, 244 (1961). 11. N . I . Shuikin and N. A. Podzdnyak, h r . AN SSSR. Otd. khim. n., 1961, 326.

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