NZ200032A - Production of chlorinated hydrocarbons from alkanes - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £00032 200032 I i • <8P- Priority Dai&i~>- ■ B S, r» r r"-^ T*'\ I •• • • 1 1 Compete Sp- ^-J-5 /"£? ~?C (7. • •••■■ jll * t"nDa-8- ./U.JUL. «B5. pabijcatjon Date.

. - No: 1?*1, " .a PtiSilt NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION PRODUCTION OF CHLORINATED HYDROCARBONS X/ We, IMPERIAL CHEMICAL INDUSTRIES PLC of Imperial Chemi cal House, Millbank, London SW1P 3JF, England, a British Company J**?, ^ MAR 1932' K hereby declare the invention for which it / we pray that a patent may be granted to ncoe/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 - (followed by page la) 200032 i<sc PRODUCTION" OF CHLORINATED HYDROCARBONS The present invention relates to a process for the selective production of chlorinated hydrocarbons by the chlorination and/or oxychlorination of alkanes.

British Patent 1.172,002 describes a process for the chlorination of hydrocarbons which comprises contacting a mixture of hydrocarbon and chlorine with a zeolite catalyst at a temperature of 50°C to 250°C temperatures of from 65°C to 150°C being most preferred.

Although this patent envisages the use of a wide variety of both hydrocarbon starting materials and zeolites (including metal exchanged zeolites), the only exemplification relates to the chlorination of ethane and of propane. Each of the aforesaid alkane starting materials give rise to a wide spectrum of chlorinated products (including about 48% of unknown product from propane and 6-7% unknown product from ethane) and there is no marked selectivity to any particular chlorinated product.

We have now found a catalytic process which is effective for the selective production of chlorinated 32 A 2 hydrocarbons from alkanes.

According to the present invention we provide a process for the selective production of chlorinated hydrocarbons which comprises contacting an alkane having 5 2 or more carbon atoms, chlorine and optionally a source of molecular oxygen in the vapour phase at a temperature above 2 75°C in the presence of a catalyst comprising a zeolite.

The process of the invention is especially 10 applicable to the selective production of vinyl chloride from ethane, chlorine and oxygen.

A wide range of zeolites may be employed as catalysts, providing they are stable under chlorination and"Gxychlorination conditions. Suitable zeolites include 15 X-type zeolites (e.g. as described in UK Patent 1,450,411; US Patent 2,882,244), Y-type zeolites (e.g. as described in fi \ f l.k, US Patent 3,130,007) , and zeolite Nu-2 (as described in tL (Oexo Mo. 1 our copending UK Application No 8040702) .

The zeolite catalysts are preferably partially 20 or wholly exchanged with metal cations, for example one or more of copper, silver, magnesium, zinc, manganese, cobalt, nickel and lanthanide ions. The preferred catalysts comprise zeolites whgLch are partially or wholly exchanged with silver and/or manganese cations, more 25 preferably silver and manganese cations.

It will be appreciated that during chlorination the aforesaid metal cations, which may be present as metals or metal compounds e.g. oxides, may be partially 200032 3 or wholly converted under the reaction conditions to chloride during the course of the reaction.

The process of the invention is applicable to a range of alkane starting materials having 2 or more 5 carbon atoms, more particularly alkanes having 2 to 4 carbon atoms, for example ethane.

The catalysts may be employed in fixed, moving or fluidised beds of the appropriate size.

The reaction temperature is suitably in the 10 range 275-500°C, and preferably between 300 and 500°C, for example 350°C to 450°C.

The reaction is normally carried out under atmospheric or superatmospheric pressure, e.g. at a pressure in the range 1 to 100 bars. 15 The process is preferably carried out in the presence of a source of molecular oxygen, e.g. oxygen itself or oxygen enriched air since this minimises coking problems and aids zeolite stability. It is especially preferable to use oxygen in order to obtain vinyl 20 chloride selectively from ethane. Useful chlorination will however, take place in the absence of oxygen. An inert diluent such as nitrogen may also be present.

The molar ratios of alkane to chlorine are suitably in the range 10 to 1 to 1 to 10, for example 1 2 5 to 1.

The molar ratios of alkane to oxygen (when present) are suitably in the range 100 to 1 to 1 to 1, for example 2 to 1.

The products of the reaction may be isolated and 30 used as such or, if desired, may be recycled wholly or partially to the chlorination reaction in order to increase the yield of specific chlorinated products.

The invention is illustrated by the following Examples.

Example 1 A Y type zeolite of formula Na20.,Al203 . 5 .1 Si02 was 2 00032 4 saturated with 10 ml of 50% Mn(N03)2»6 1^0 solution for 16 hours and then filtered and washed thoroughly with water. The white solid was then treated with 10 ml of 80% AgN03 solution for 16 hours, filtered, washed, dried 5 at 120°C for 16 hours and then calcined at 450°C for 16 hours. The resulting catalyst was shown by analysis to contain 18.9% silver and 2.4% manganese. After grinding to 20-30 mesh size the catalyst was packed as a 10 cm bed in a •6.3. imv.O.D.. microreactor tube surrounded by a resistively 10 heated furnace and connected to an on-line GLC system.

After treatment in flowing chlorine at 400°C, the catalyst was tested with ethane over a range of gas feed compositions and temperatures. The results are shown in Table 1.

A comparative example was carried out at 400°C 15 in which t.he silver/manganese/zeolite catalyst was replaced by an equal quantity of pumice ground to the same mesh size. The results are shown in Table 2. A comparison of these results with those shown in Table 1 illustrates the greater selectivity to vinyl chloride when using the silver/ 20 manganese/zeolite catalyst..

Example 2 A catalyst was prepared as in Example 1 but from offretite zeolite, analysis showing the resultant material to contain 12.1% silver and 0.6% manganese. The following results 25 were obtained with a feed mixture of chlorine, ethane and air at 365°C.

Example 3 The sodium form of X type zeolite (Molecular sieve 13X) was exchanged with silver and manganese by contacting for 30 24 hours with an equimolar concentrated solution of manganous and silver nitrates. After filtration, the zeolite was washed arrd dried at 450°C overnight. The resultant powder was found to contain 23.9 weight % silver and 3.4 weight % manganese. The catalyst was tested as 35 in Example 1 to give the results.presented, in Table 4.

TABLE 1 Reaction Tertp °C Gas C2H6 feed (ml/min) Air CI2 Conversion (C2Hg mol %) Selectivity % 1 VC C2H4 EtCl Trans Dichlor Cis Dichlor EDC g-Tri co2 375 2 2 53.9 43.3 21.1 0.9 .1 11.5 4.3 3.0 9.1 400 2 2 40.6 .8 18.0 0.6 .4 11.3 17.8 1.7 7.3 TABLE 2 feed (ml/min) Air Cl2 Selectivity % Reaction Tenp °C Gas C2H6 Conversion (C2Hg mol %) VC C2H4 EtCl Trans Dichlor Cis Dichlor EDC g-Tri co2 350 5 18.8 0.6 90.1 - - 3.6 - 0.6 420 5 14.4 0.3 .8 87.9 - - 4.0 0.6 0.4 Notes on Tables 1 and 2 VC = vinyl chloride Trans dichlor = trans dichloroethylene Cis dichlor = cis dichloroethylene EDC = ethylene dichloride B-tri = B-trichloroethane TABLE 3 Gas feed (ml/min) C^g Air Cl2 Conversion (C2Hg mol %) Selectivity % VC C2H4 EtCl Trans Dichlor Cis Dichlor EDC B Tri C°2 2 10 2 67.6 46.2 16.9 0.6 .2 13.6 6.1 1.6 7.6 2 10 1 47.7 45.6 22.7 0.8 3.9 .3 3.5 2.3 8.6 Notes on Table 3 VC = vinyl chloride Trans dichlor = trans dichloroethylene Cis dichlor = cis dichloroethylene EDC = ethylene dichloride B-tri = 6-trichloroethane

Claims (7)

TABLE 4 Gas Feed (ml/min) Conversion Selectivity % c2h6 Air cl2 (C2Hg mol%) VC C2H4 EtCl Trans Dichlor Cis Dichlor EDC TRI co2 2 10 3 81 10 31 44 - - 2.6 - 2 2 10 4 99 34 28 18 - - 7 0.5 2 2 10 6 42 25 1 3 10 8 2.6 2 2 10 8 100 11 0.3 - 18 ' 32 4 21 10 TRI = Trichlorethylene fs) O O o GJ Is) 2 00032 A 8 WHATT/WE CLAIM IS: CLAIMS-"

1. A process for the selective production of chlorinated hydrocarbons which comprises contacting an alkane having 2 or more carbon atoms, chlorine and optionally a source of molecular oxygen in the vapour phase at a temperature above 2 75°C in the presence of a catalyst comprising a zeolite.

2. A process according to claim 1 wherein ethane, chlorine and oxygen are contacted in the presence of the catalyst to form vinyl chloride.

3. A process according to claim 1 or claim 2 wherein the catalyst comprises a zeolite that has been partially or wholly exchanged with silver and/or manganese cations.

4. A process according tc any one of the preceding claims wherein the reaction temperature is in the range 300° to 500°C.

5. A process according to any one of the preceding claims wherein the molar ratio of alkane to chlorine is in the range 10:1 to 1:10.

6. A process according to any one of the preceding claims wherein the molar ratio of alkane to oxygen is in the range 100:1 to 1:1.

7. A process according to claim 1 substantially as hereinbefore described with reference to the foregoing Examples. dated this day of (11902. a. j. park & son per fa. agents for the applicants