Process for the acylation of aromatic compounds using a...

Details Process for the acylation of aromatic compounds using a... Process for the acylation of aromatic compounds using a...

2000-11-28

2002-08-20

Padmanabhan, Sreeni (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

C568S309000, C568S322000, C568S323000

Reexamination Certificate

active

06437191

ABSTRACT:

FILED OF THE INVENTION
The present invention relates to a process for the liquid phase acylation of aromatic compounds using a solid catalyst comprising indium halide. This invention particularly relates to a process for the acylation of aromatic compounds for preparing acylated aromatic compounds using a reusable solid catalyst comprising indium halide.
The process for this invention could be used for the preparation of acylated aromatic compounds, which are fine chemicals and/or used as intermediates in the preparation of fine chemicals or speciality chemicals in dyes and pharmaceutical industries and other chemical industries.
BACKGROUND OF THE INVENTION
Prior art discloses both homogeneous and heterogeneous liquid phase processes based on Friedel-Crafts type reactions for the preparation of acylated aromatic compounds.
Friedel-Crafts Type Acylation Reactions Catalyzed by Homogeneous Catalysts
The Friedel-Crafts type acylation of aromatic compounds by various acylating agents using homogeneous Lewis Acid catalysts, such as AlCl
3
, BF
3
, ZnCl
2
and other metal chlorides and protonic acid catalysts, such as H
2
SO
4
, H
3
PO
4
, HF, etc., are well known in the prior art (ref G. A. Olah, in Friedel-Crafts and related reactions: vol. III, Acylation and related reactions, Wiley-Interscience Publ., New York, 1964).
U.S. Pat. No. (5,476,970 (1995)) of Rains et al., discloses a homogeneous liquid phase process for the acylation of R
1
,R
2
C
6
H
4
by R
3
R
4
C
6
H
3
COCl, wherein R
1
, R
2
, R
3
and R
4
are chemical groups, using FeCl
3
catalyst at high pressures. French patent (FR 2768728 (1999)) and (FR 2768729 (1999)) of Baudry et al., discloses liquid phase homogeneous process for the benzoylation of anisole by benzoyl chloride using rare earth halides or uranyl halide.
Japanese Patent (JP 08277241, A2 (1996)) of Kunikata discloses a liquid phase process for the acylation of phenol by phenyl acetyl chloride using a homogeneous AlCl
3
catalyst. Japanese Patent (JP 09059205, A2 (1997)) of Oono discloses the use of AlCl, as a homogeneous catalyst for the acylation of toluene with acetyl chloride at high pressure.
Japanese Patent (JP 2000086570, A2 (2000)) of Shoji et al., discloses a homogeneous liquid phase process for the acylation of toluene by acetyl fluoride using HF-BF, as a catalyst.
The main disadvantages of the Friedel-Crafts type acylation processes based on the use of above mentioned homogeneous acid catalysts 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.
Friedel-Crafts Type Acylation Reactions Catalyzed by Heterogeneous Solid Catalysts
A few liquid phase processes for the acylation of aromatic compounds by acyl halides using solid catalysts are also known in the prior art.
Japanese Patent (JP 01089894, A2 (1995)) of Myata et al., discloses a liquid phase process for the acylation of toluene with benzoyl chloride using ammonium chloride treated H-beta zeolite catalyst under reflux for
3
h
to get para-acylated toluene with 28% yield. French Patent (FR 2745287, A1 (1997)) of Barbier et al. discloses the liquid phase acylation of anisole by benzoyl acloride under reflux using neodymium chloride deposited on montmorillonite K-10 clay.
Vincent et al., (ref Tetrahedron Lett. 35, 1994, 2601) discloses that H-ZSM-5 zeolite can catalyze the acylation by benzoyl chloride of phenol and anisole but not the acylation with benzoyl chloride of benzene and naphthalene at 120° C. for 5 h.
Acylation of aromatic compound involves electrophilic substitution of H from the aromatic nucleus of the aromatic compound. 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. Whereas the electrophilic substitution is inhibited by the presence of electron withdrawing groups such halo, nitro, cyano, carboxy, aldehyde, etc., in the aromatic compound (ef. G.A.Olah, in Friedel-Crafts and related reactions, Wiley-Interscience Publ., New York, 1963).
Although some limitations of the homogeneous acid catalyzed process are overcome in the prior art heterogeneous solid catalyzed processes described above, the acylating activity of the solid acid catalysts used in the prior art processes is low, particularly for acylating aromatic compounds not containing electron donating groups, such as benzene, naphthalene, etc. Both the prior art homogeneous and heterogeneous acid catalysts are highly moisture sensitive, and hence demand moisture-free or thoroughly dried reactants, solvents and catalyst for the Friedel-Crafts type acylation processes. In presence of moisture in the reaction mixture homogeneous and heterogeneous catalysts show poor activity in the Friedel-Crafts processes. Hence, there is a great practical need for finding more efficient and also moisture insensitive solid catalyst for the acylation of aromatic compounds.
The main object of this invention is to provide a liquid phase process for the acylation of aromatic compounds, including those not containing electron donating groups using novel solid catalyst which has high activity not only when the aromatic ring activating groups (i.e. electron donating groups such as alkyl, alkoxy, hydroxy, phenoxy, etc.) are present in the aromatic ring to be acylated but also when the ring activating group in the aromatic ring to be acylated is absent, so that the reaction temperature is low and or time for completing the reaction is shot.
Another object of this invention is to provide a liquid phase process for the acylation of aromatic compounds, using a novel solid catalyst which is easily separable and reusable in the process.
Yet another object of this invention is to provide a solid catalyzed liquid phase process for the acylation of aromatic compounds event in the presence of moisture in the reacon mixture.
SUMMARY OF THE INVENTION
Accordingly the present invention provides a process for the liquid phase acylation of an aromatic compound (1) of the formula (R
1
,R
2
R
3
R
4
)—D—H by an acylating agent (II) of the formula (R
5
R
6
R
7
)—Y—Z to produce corresponding acylated aromatic compound (III) of the formula ((R
1
, R
2
R
3
R
4
)—D—Y—(R
5
R
6
R
7
), wherein D is an aromatic nucleus selected from side aromatic ring containing 6 C-atoms and 1 H-atom or fused two aromatic rings containing 10 C-atoms and 3 H-atoms and three fused aromatic rings containing 14 C-atoms and 5 H-atoms; R
1
, R
2
,R
3
and R
4
are chemical groups attached to the aromatic nucleus, D; Y is a nucleus of the acylating agent selected from the group consisting of C—CO, C
n
H
2n−2
CO, C
6
H
2
—CO, C
6
H
2
C
n
H
2n
—CO and C
6
H
2
C
n
H
n2−1
(X)-CO; R
5
, R
6
and R
7
are chemical groups attached to the nucleus of acylating agent Y; Z is selected from Cl, Br and I; X is a halogen group; and n is an integer ≧1.0, using a solid catalyst (IV), comprising indium halide, represented by a formula M
x
In
1−x
Ay(a)/S wherein S is a porous catalyst support selected from clays, zeolites and zeolite-like materials; M is a metallic chemical element selected from the group consisting of Ga, Fe, Zn, Ti ox a mixture of two or more thereof; A is a non-metallic chemical element selected from the group consisting of Cl, Br, I, F and a mixture of two or more thereof, x is a mole fraction of M and is in the range from 0.01 to 0.99; y is the number of A atoms required to satisfy the valence requirement of M
x
In
1−x
; and a is a loading of M
x
In
1−x
A on the support S and is in the range of from 0.05 mmol.g
−1
to 5.0 mmol.g
−1
; said process comprising:
i) pretreating said catalyst (IV) under vacuum or flow of an inert gas selected from nitrogen, helium and argon at a t

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