Title of Invention

AN IMPROVED PROCESSS FOR THE MANUFACTURE OF EPICHLOROHYDRIN.

Abstract An improved process for the manufacture of epichlorohydrin by reacting allyl chloride with source of molecular oxygen in the presence of a solid catalyst containing pthalocyanine having transition metal wherein some or all of the hydrogen atoms of the pthalocyanine have been substituted by one or more electron withdrawing groups, at a temperature in the range of 20°C to 90°C, at a pressure in the range of 5 to 1000 psi optionally in the presence of aliphalic solvent and/or promoter and isolating the epichlorohydrin formed by conventional methods.
Full Text This invention relates to an improved process for the manufacture of epichlorohydrin by the oxidation of allyl chloride. More particularly, the present invention relates to a process for the manufacture of epichlorohydrin by the oxidation of allyl chloride using molecular oxygen as the oxidant and a solid organotransi-tion metal complex as a catalyst.
Epichlorohydrin is a useful intermediate in the manufacture of a wide variety of products. The oxirane functionality in epichlorohydrin is highly reactive and may be ring opened with any number of nucleophilic reagents. For example, the epoxide ring may be hydrolysed to yield glycols or reactive monomers for the preparation of condensation polymers.
Many different methods for the preparation of epichlorohydrin have been developed in the prior art. In current commercial practice epichlorohydrin is manufactured by the epoxidation of allyl chloride by calcium hypochlorite. One major drawback in such process is the necessity to dispose off large quantities of the low value byproduct, calcium chloride in an environmentally acceptable manner. Approximately one equivalent of calcium chloride coproduct is obtained for each equivalent of epichlorohydrin. Another method known in the prior art for the preparation of epichlorohydrin involves the use of certain titanium silicate compounds to catalyse allyl chloride oxidation by hydrogen peroxide. This method is described, for example in U.S.
Patents 4, 824, 976 (Clerici et al) and 4, 833, 260 (Neri et al). Even though letter process does not generate environmentally harmful low value coproducts which have to be disposed off, it is economically less viable since it involves the use of the more expensive hydrogen peroxide as the source of oxygen and hence has not been adopted in common commercial practice.
Development of a process which uses the less expensive molecular oxygen as the oxidant for oxidation of allyl chloride to epichlo-rohydrin, does not generate environmentally harmful effluents and preferably uses a solid catalyst for the oxidation reaction is desirable.
It is, therefore, an object of the present invention to provide an improved process for the manufacture of epichlorohydrin by the oxidation of allyl chloride using an oxygen - containing gas as the oxidant.
In accordance with the present invention, it has now been found that allyl chloride may readily be oxidised with air selectively to epichlorohydrin in the presence of certain solid catalysts containing particular organotransition metal complexes. The use of these catalysts in the process of oxidation of allyl chloride results in several unexpected advantages. The catalyst remains in the solid state at the end of the oxidation reaction thereby facilitating the easy separation, recovery and recycle of the
catalyst from the reaction products without having any adverse impact on the environment.
The oxidation of compounds containing carbon-carbon double bonds with molecular oxygen is known in the prior art to yield the allylic oxidation products rather than the epoxide. Thus, the air oxidation of propylene yields mainly acrolein rather than the epoxide propylene oxide. Similarly, the air oxidation of styrene yields benzaldehyde rather than the epoxide styrene oxide (see E.R. Birnbaum et al Journal of Molecular Catalysis, A, 104 (1995) pp L119-L122).
We have now made the unexpected discovery that when allyl chloride is reacted with molecular oxygen in the presence of certain solid catalysts containing an organotransition metal complex wherein some or all of the hydrogen atoms of the said organotransition metal complex have been substituted by one or more electron withdrawing groups, the epoxidation product epi-chlorohydrin rather than products arising from allylic oxidation is formed in a highly selective manner.
In an embodiment of the present invention the organotransition metal complex is a pthalocyanine.
In another embodiment of the present invention, the transition metal is selected from iron, cobalt, copper, chromium , manganese or mixtures thereof.
Some nonlimiting examples of such organo transition metal complexes used as catalysts in the oxidation of allyl chloride to epichlorohydrin are iron halopthalocyanines, copper, halo pthalocyanines, cobalt halo pthalocyanines, chromium halo pthalocya-nines, manganese halo pthalocyanines, iron nitro pthalocyanines, copper nitro pthalocyanines, chromium nitro pthalocyanines, cobalt nitro pthalocyanines, manganese nitro pthalocyanines, manganese cyano pthalocyanines, copper cyano pthalocyanines and chromium cyano pthalocyanines.
In yet another embodiment of present invention the electron withdrawing groups attached to the organotransition metal complex is selected from the halogens, fluorine, chlorine or bromine or the nitro or cyano groups.
In a preferred embodiment of the present invention, the oxidation of allyl chloride by molecular oxygen is catalysed by the halogen, cyano or nitro pthalocyanines of the metals iron, cobalt, copper, chromium or manganese.
In yet another embodiment of the present invention, the source of molecular oxygen can be pure oxygen gas, air or a mixture of oxygen and an inert gas diluent like nitrogen.
In yet another embodiment of the present invention, the above mentioned oxidation reaction can be carried out in the presence or absence of solvents. It may be an advantageous option to
carry out the said oxidation reaction in the presence of a suitable solvent which would maintain the oxidation products like epichlorohydrin in the dissolved state during the course of the reaction, thereby facilitating the separation of the said epichlorohydrin from the solid catalysts. Suitable solvents for such use include acetonitrile, methanol, water, butanol and cyclohexanol. Examples of such solvents which can be used in the process of the present invention include acetonitrile, acetone, benzene or any other organic solvent which is inert under the oxidation reaction conditions.
In one advantageous embodiment of the present invention, the rates of the oxidation of allyl chloride to epichlorohydrin may be significantly enhanced by addition of very small catalytic quantities of a promoter. Examples of such promoters include alkyl hydroperoxide, dialkylperoxides and such compounds. Cyclo-hexyl hydroperoxide, cumyl peroxide, tertiary butyl hydroperoxide are some of the examples of such promoters which may be present in concentrations not exceeding 1% by weight of allyl chloride and more preferably 0.1% by weight of allyl chloride.
In yet another advantageous embodiment of the present invention, the organotransition metal complex may be encapsulated in a solid matrix. Due to the greater dispersion of the organotransition metal complex catalyst in solid matrices and the consequent enhanced stability of the structural integrity of the catalyst significant process advantages like greater activity, stability
and easy recovery and recyclability of the catalyst are observed. Examples of such solid matrices include inorganic oxide like silica, alumina, molecular sieves, zeolites and the like as well as organic polymeric material.
It is an advantageous feature of the process of the present invention that due to the high activity the catalysts used herein, the oxidation reaction can be carried out at temperatures much below those used in the prior art and preferably below 90°C, thereby leading to much lower yields of undesired side products.
The details of the present invention is described in the examples given below which are provided by way of illustration only and therefore should not be construed to limit the scope of the invention.
Example-1
In an autoclave, 5 g of allyl chloride and 0.3 g of solid iron tetra deca bromo pthalocyanine were stirred at 60°C with a continuous bubbling of air for 8 hrs. At the end of the reaction, the products were separated from the solid catalyst by centrifu-gation and analysed by gas chromatography (Shimadzu GC RlA) using a carbowax column and flame ionization detector (FID). The identity of the products was confirmed by GC mass spectroscopy
(Shimadzu GCMS-QP 2000A) using standard compounds. The conversion of allyl chloride was 12% wt and the yield of epichlorohy-drin was 11% wt.
Example-2
In an autoclave, 5 g of allyl chloride and 0.3 g of solid cobalt tetra deca chloro pthalocyanine were stirred at 60°C with a continuous bubbling of air for 8 hrs. At the end of the reaction, products were separated from the solid catalyst by cen-trifugation and analysed by gas chromatography (Shimadzu GC R1A) using a carbowax column and flame ionization detector (FID). The identity of the products was confirmed by GC mass spectroscopy (Shimadzu GCMS-QP 2000A) using standard compounds.The results are given in Table 1.
Example-3
In an autoclave, 5 g of allyl chloride and 0.3 g of solid copper tetra deca chloro pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The results are given in Table 1.
Example-4
In an autoclave, 5 g of allyl chloride and 0.3 g of solid chromium tetra deca fluoro pthalocyanine were stirred at 50°C with a
continuous bubbling of air for 8 hrs. The products are given in Table 1.
Example-5
In an autoclave, 5 g of allyl chloride and 0.3 g of solid manganese tetra deca fluoro pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The products are.given in Table 1.
Table 1 indicates the wt % conversion of allyl chloride and wt % yield of epichlorohydrin when using different organotransition metal complexes as catalysts and using the conditions mentioned herein above (Examples 2-5)
Table 1
(Table Removed)
Example-6
In an autoclave, 5 g of allyl chloride and 0.3 g of solid iron deca nitro pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The products are given in Table 2.
Example-7
In an autoclave, 5 g of allyl chloride and 0.3 g of solid cobalt deca nitro pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The products are given in Table 2.
Example-8
In an autoclave, 5 g of allylchloride and 0.3 g of solid copper deca nitro pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The products are given in Table 2.
Example-9
In an autoclave, 5 g of allyl chloride and 0.3 g of solid chromium deca nitro pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The products are given in Table 2.
Example-10
In an autoclave, 5 g of allyl chloride and 0.3 g of solid manganese deca nitro pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The products are given in Table 2.
Table – 2
(Table Removed)
Example-11
In an autoclave, 5 g of allyl chloride and 0.3 g of solid iron tricyano pthalocyanine were stirred at 60°C with a continuous bubbling of air for 8 hrs. The yield of epichlorohydrin was 10 % wt.
Example-12
In an autoclave, 5 g of allyl chloride and 0.3 g of solid cobalt tricyano pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The yield of epichlorohydrin was 16 % wt.
Example-13
In an autoclave, 5 g of allyl chloride and 0.3 g of solid copper tricyano pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The yield of epichlorohydrin was 18 % wt.
Example-14
In an autoclave, 5 g of allyl chloride and 0.3 g of solid chromium cyano pthalocyanine were stirred at 50"C with a continuous bubbling of air for 8 hrs. The yield of epichlorohydrin was 9 % wt.
Example-15
In an autoclave, 5 g of allyl chloride and 0.3 g of solid manganese cyano pthalocyanine were stirred at 50°C with a continuous bubbling of air for 8 hrs. The yield of epichlorohydrin was 14 % wt.
Example-16
In an autoclave, 5 g of allyl chloride, 0.3 g of solid iron tetra deca bromo pthalocyanine, 5 g of acetonitrile solvent, and 0.08 g of tert. butyl hydroperoxide promoter were stirred at 50°C with a continuous bubbling of air for 8 hrs. The conversion of allyl chloride was 20% and the yield of epichlorohydrin was 18% wt.
Example-17
In an autoclave, 5 g of allyl chloride, 0.3 g of solid iron tetra deca chloro pthalocyanine, 5 g of methanol solvent, and 0.08 g of tert. butyl hydroperoxide promoter were stirred at 50°C with a continuous bubbling of air for 8 hrs. The conversion of allyl chloride was 22% and the yield of epichlorohydrin was 19% wt.
Example-18
In an autoclave, 5 g of allyl chloride, 0.3 g of solid copper tetra deca chloro pthalocyanine, 5 g of methanol solvent, and 0.08 g of ditert. butyl peroxide promoter were stirred at 50"C with a continuous bubbling of air for 8 hrs. The conversion of allyl chloride was 16% and the yield of epichlorohydrin was 15% wt.
Example-19
In an autoclave, 5 g of allyl chloride, 0.3 g of solid copper tetra deca bromo pthalocyanine encapsulated in the aluminosili-cate molecular sieve-Y, 5 g of methanol solvent, and 0.08 g of ditert. butyl peroxide promoter were stirred at 50°C with a continuous bubbling of air for 8 hrs. The conversion of allyl chloride was 22% and the yield of epichlorohydrin was 16% wt.
Example-20
In an autoclave, 5 g of allyl chloride, 0.3 g of solid copper tetra deca chloro pthalocyanine encapsulated in an organic polymer, 5 g of methanol solvent, and 0.08 g of ditert. butyl peroxide promoter were stirred at 50 °C with a continuous bubbling of air for 8 hrs. The conversion of allyl chloride was 18% and the yield of epichlorohydrin was 16% wt.





We claim :
1. An improved process for the manufacture of allyl chloride which comprises reacting allyl chloride with molecular oxygen in the presence of a solid catalyst containing an organotransition metal complex wherein some or all of the hydrogen atoms of the said organotransition metal complex have been substituted by one or more electron withdrawing groups, at a temperature in the range of 20°C to 90°C, at a presure in the range of 5 to 1000 psi in the presence or absence of solvents, with or without promoter and isolating the epichlorohydrin formed by conventional methods.
2. An improved process according to claim 1 wherein the organo
transition metal complex is a pthalocyanine.
3. An improved process according to claims 1-2 wherein the
transition metal is selected from iron, cobalt, copper,
chromium, manganese or mixtures thereof.
4. An improved process according to claim 1 wherein the said
electron withdrawing group is selected from the halogens,
the nitro group, the cyano group or mixtures thereof.
5. An improved process according to claims 1-5 wherein the
source of molecular oxygen is oxygen, air or a mixture of
oxygen and an inert gas like nitrogen.
6. An improved process according to claims 1-5 wherein the
oxidation reaction is carried out in the presence of sol
vents such as acetonitrile, methanol, butanol and cyclohexa-
nol.
7. An improved process according to claims 1-6 wherein a
promoter such as alkyl hydroperoxide, dialkyl peroxide or
mixtures thereof is used in the reaction.
8. An improved process according to claims 1 to 7 wherein the
concentration of the promoter in the reaction mixture does
not exceed 1% by weight of the allyl chloride.
9. An improved process according to claims 1 to 8 wherein the
organotransition metal complex is encapsulated in a solid matrix.
10. An improved process according to claim 9 wherein the solid
matrix used is an inorganic oxide such as silica, alumina,
aluminosilicates or molecular sieves.
11. An improved process according to claim 10 wherein the solid
matrix is an organic polymer.
12. An improved process according to claim 10 wherein the solid
matrix contains both an inorganic oxide and an organic poly
mer.
13. An improved process for the oxidation of allyl chloride to
epichlorohydrin substantially as herein above with reference
to the Examples.

Documents:

661-DEL-1996-Abstract.pdf

661-DEL-1996-Claims.pdf

661-del-1996-complete specification (granted).pdf

661-DEL-1996-Correspondence-Others.pdf

661-DEL-1996-Correspondence-PO.pdf

661-DEL-1996-Description (Complete).pdf

661-DEL-1996-Form-1.pdf

661-DEL-1996-Form-2.pdf

661-DEL-1996-Form-3.pdf

661-DEL-1996-Form-4.pdf


Patent Number 212647
Indian Patent Application Number 661/DEL/1996
PG Journal Number 50/2007
Publication Date 14-Dec-2007
Grant Date 10-Dec-2007
Date of Filing 27-Mar-1996
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 PAUL RATNASAMY NATIONAL CHEMICAL LABORATORY, PUNE, INDIA.
2 ROBERT RAJA NATIONAL CHEMICAL LABORATORY, PUNE, INDIA.
PCT International Classification Number C07D 303/08
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA