Process for the preparation of aralkylated aromatic...

Details Process for the preparation of aralkylated aromatic... Process for the preparation of aralkylated aromatic...

1999-01-11

2001-04-10

Tran, Hien (Department: 1764)

Chemistry of hydrocarbon compounds

Aromatic compound synthesis

By condensation of entire molecules or entire hydrocarbyl...

C585S454000, C585S469000, C558S369000, C560S203000, C562S093000, C564S409000, C568S628000

Reexamination Certificate

active

06215035

ABSTRACT:

This invention relates to a process for the preparation of alkylated aromatic compound by catalytic alkylation of aromatic compound with aromatic alkylating agent using a solid catalyst. This invention particularly relates to the preparation of aralkylated aromatic compound by catalytic aralkylation of aromatic compound with aromatic alkylating agent using a solid catalyst comprising of gallium.
The process for this invention could be used for the preparation of alkylated aromatic compounds, which are fine chemicals and/or used in the preparation of fine chemicals.
Aralkylated aromatic compounds are useful fine chemicals, these are also used as intermediates in a number of organic synthesis. Both the homogeneous and heterogeneous catalysed liquid phase processes for the preparation of aralkylated aromatic compounds are known in the prior art.
Homogeneous Acid Catalysed Processes
According to a U.S. patent, U.S. Pat No. 3,678,122(1972), diphenylmethane was prepared by treating a mixture of benzene and benzyl chloride with CuCl
2
. A U.S. patent, U.S. Pat. No. 3,679,760(1972), disclosed the preparation of diaryl alkanes by refluxing benzyl chloride, C
6
H
4
R
1
R
2
(where R=H and R
2
=H, CH
3
or OH) and CuCl
2
.
A French patent, Fr. Demande 2,144,578(1973), disclosed that substituted phenols p-RC
6
H
4
OH (where R=halogen or C
1-4
-alkyl) are benzylated by benzyl halides in the presence of ZnCl
2
. A USSR patent, U.S.S.R. 394,353(1973), disclosed preparation of 2,6 and 2,4-(CH
3
O)
2
C
6
H
3
CH
2
C
6
H
5
by treating m-(CH
3
O)
2
C
6
H
4
with benzyl chloride in the presence of SnSO
4
catalyst at 145-150° C., or SnCl
2
catalyst at 165-170° C. A Japanese patent, Japan Kokai 7399,154(1973), disclosed preparation of dibenzyl benzene derivatives by benzylation of benzene or substituted benzenes using Friedel-Crafts catalyst e.g., AlCl
3
, FeCl
3
and 98% H
2
SO
4
According to this patent, 200 g &agr;-methyl benzyl chloride was added to a refluxing mixture of 500 g benzene and 5 g AlCl
3
and the whole mixture refluxed for 5 h to give 120 g &agr;-methyl bezylbenzene.
According to a German patent, Ger. Offen 2,456,747 (1976), o-benzyltoluenes were prepared in ~90% yields by the reaction of &agr; o-chloromethyltoluene with a benzene derivative in ≧1:7 ratio in the presence of H
2
SO
4
and/or H
3
PO
4
and optionally 4-CH
3
C
6
H
4
SO
3
H, ZnCl
2
, BF
3
, etc. Thus 135 parts 85% H
3
PO
4
, 270 parts 85% H
2
SO
4
, 10 parts 4-CH
3
C
6
H
4
SO
3
H, 70 parts 2CH
3
C
6
H
4
CH
2
Cl and 390 parts of C
6
H
6
were heated at 75-80° C. for 4 h to give 89% 2-CH
3
C
6
H
4
CH
2
C
6
H
5
.
An US Patent U.S. Pat. No. 4,049,733 (1977), disclosed preparation of diphenylmethane by benzylation of benzene with benzylether using phosphoric acid and optionally H
2
SO
4
or a Friedel-Crafts type metal halide.
European patent, Eup.Pat.Appl.EP 37,628 (1981), disclosed preparation of diphenylmethane by benzylation of benzene with chloromethylbenzenes in the presence of H
2
SO
4
and a cationic surfactant or a non-ionic surfactant which is susceptible to protonation under strong acidic conditions.
A German patent, Ger.Offen DE 3,922,518 (1991), disclosed a process for the manufacture of &agr;-methylbenzylphenol derivatives, which comprises the treatment of C
1-4
-alkyl substituted phenols with styrene in the presence of phosphorus chloride catalyst. More recently, an European Patent, Eur.Pat.Appl.EP 538,704 (1993), disclosed a process for the preparation of p-substituted o-benzylphenols by treating phenols, p-R′C
6
H
4
OH (R′=halo, alkyl, OH, alkoxy, ikylmercapto, aryl, aryloxy. or arylmercapto), with ArCH
2
X (Ar=corresponding aryl nucleus; X=halo, arylcarboxy, phenylsulfatoxy, hydroxy, alkoxy etc.) in a continuously functioning distillation apparatus in the presence of dissolved acid catalyst.
The main disadvantages of the homogeneous acid catalyzed processes are as follows:
1) The separation and recovery of the dissolved acid catalysts from the liquid reaction mixture is difficult.
2) The disposal of the used acid catalysts creates environmental pollution.
3) The homogeneous acid catalysts also pose several other problems such as high toxicity, corrosion, spent acid disposal and use of more than the stoichiometric amount.
Heterogeneous Acid Catalyzed Processes
A German patent, Ger.Offen 2,547,030 (1977), disclosed the preparation of o-benzyltoluenes by the reaction of o-methylbenzyl halides with substituted benzenes in the presence of Al-silicate. The 2-CH
3
C
6
H
4
CH
2
Cl was stirred with toluene and Al-silicate (25% Al
2
O
3
) at 110° C. to give 81% 2-methylbenzyltoluene. According to a Japanese patent, Jpn. Kokai Tokkyo Koho JP 59,186,937 (1984), o-benzylphenol was prepared by the liquid phase reaction of benzyl alcohol with phenol in the presence of &lgr;-Al
2
O
3
. For exanple 7.5 g &ggr;-Al
2
O
3
was added to a mixture of 32.5 g benzyl alcohol and 47 g phenol at 190° C. under stirring to give a product containing 49.9% o-benzylphenol. A German Patent, Ger. Offen DE 3,700,917 (1988), disclosed the preparation of p-substituted o-benzylphenols by benzylation of p-substituted phenols with benzylalcohol in the presence of Na-Y type zeolite. A mixture of 0.5 mole 4-ClC
6
H
4
OH, 0.1 mole C
6
H
5
CH
2
OH and 0.6 g of Na-Y type zeolite was heated at 200° C. for 3 hrs to give 25.4% 2-benzyl-4-chlorophenol.
A German patent, Ger. Offen DE 3,836,780 (1990), disclosed thesprocess for the preparation of benzylbenzenes from benzenes and benzyl alcohols in the presence of activated bleaching earth and a diluent at 90-140° C. According to Japanese patent, Jpn Kokai Tokkyo Koho JP 03,170,442 (1991), benzylbiphenyls are manufactured by benzylating biphenyl and diphenylmethane with ≧1 compound from benzyl halides, benzyl alcohol, benzyl ether in the presence of a zeolite or silica-alumina catalyst. An European patent, Eur.Pat. appl. EP 428,081 (1991), disclosed a process of benzylation of alkylbenzenes with benzyl chloride in the presence of H—Y or H—L zeolite catalyst. According to a Gerrnan patent, Ger. Offen DE 4,038,933 (1992), disclosed a process for benzylation of aromatics using technical carbon catalysts.
Aralkylation of aromatic compounds by aralkylating agent involves electrophilic substitution of H from the aromatic nucleus. It is well known, in the prior art that the electrophilic substitution is favoured by the presence of electron donating groups, such as OH, alkyl, alkoxy, phenoxy, amine, alkyl amine, SH etc., in the aromatic compound to be aralkylated. Whereas the electrophilic substitution is inhibited by the presence of electron withdrawing groups such as halo, nitro, cyano, carboxy, aldehyde, etc., in the aromatic compound to be aralkylated. [ref. G. A. Olah, in Friedel-Crafts and related reactions, Wiley-Interscience Publ., New York, 1963].
Although some limitations of the homogeneous acid catalyzed processes are overcome by the prior art heterogeneous catalyzed processes described above, the aralkylating activity of the solid catalysts used in the prior art processes are low, particularly for aralkylating aromatic compounds containing electron withdrawing groups. Hence there is a great practical need for finding more efficient solid catalyst for the aralkylating of aromatic compounds. There is also a need for finding highly efficient solid catalyst also for the aralkylating of aromatic compounds containing electron withdrawing groups such as halo, nitro, cyano, carboxy, aldehyde, etc. This invention is, therefore, made with the following objects so that most of the drawbacks or limitations of the prior art homogeneous and heterogeneous catalyzed processes for the preparation of aralkylated aromatic compounds could be overcome.
OBJECTS OF THE INVENTION
1. Accordingly, the main object of this invention is to provide a liquid phase process for the preparation of aralkylated aromatic compound by aralkylating aromatic compound with aralkylating agent, using a highly active solid catalyst comprising of gallium, which has high acti

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