DE1907088A1 - Process for the production of methyl chloride - Google Patents

Description

H / He (69) The Dow Chemical Company, Midland, Michigan, TJ. SoA.

Dow Case 12,818-F

Process for the production of methyl chloride

This invention "relates to an improved method of manufacture of methyl chloride and relates in particular to a process in which a mixture of methanol and hydrogen chloride with gamma-alumina at a temperature of at least 150 ° C and a pressure of at least one atmosphere is brought into contact.

It has been found that in the production of methyl chloride by reacting methanol and hydrogen chloride in the presence of gamma-aluminum oxide, the yields and the Conversions improve in a surprising manner and at the same time the losses attributable to the formation of dimethyl ether can be reduced significantly by carefully controlling the ratio of methanol and hydrogen chloride and avoid excessively high temperatures. The essential features of the invention are that a Mixture of 0.75 to 1.1 mole parts of methanol for each mole part of hydrogen chloride with gamma-alumina contributing a temperature of 150 ° C to 500 ° C is brought into contact. The mixture preferably contains 0.95 to 1 mole fraction Methanol for each mole fraction of hydrogen chloride and it is preferably used at temperatures of 289 ° C to 360 ° C for the Contact with the catalyst worked.

Although it is advantageously a substantially anhydrous tlischung from methanol and hydrogen chloride to be used, but also an aqueous solution which advantageously at least 15 G-ew may. Contain ° / o Ghlorwasserstoff be mixed with the methanol in the method of the invention. The response is in

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usually at an increased pressure of preferably 1.5 "to 10 atmospheres executed "

As already indicated, a small excess of .an Methanol can be permitted, although this is usually avoided. However, if an excess of methanol is used, The only undesirable by-product is dimethyl ether. Difficulties are then encountered in obtaining the methyl chloride in pure form, since the ether, once present, is released from it Methyl chloride is difficult to separate by distillation. Up to

. However, about 0.1 Uolfo excess methanol may be tolerated in the invention ER *.

The reaction can be carried out well at reaction temperatures of Perform 150 ° 0 to 500 C. Preferably the Reaki but carried out at temperatures between 289 and 360 ° C.

The material used as a catalyst in the invention is an activated alumina which can be obtained by heating the Monohydrates (AIgO ^ -HpO) to at least about 300 ° C. At least part of the water of crystallization is removed and the crystalline structure of the material is reoriented to to get the gamma form, this material being less than contains a larger proportion of alpha aluminum oxide "

The method of the invention is conveniently used a fixed catalyst carried out, although the catalyst is also used in the "fluidized bed" can. However, the use of a fluidized bed reduces the cost of the process both in terms of equipment and the operating mode increased. In addition, when working in a fluidized bed, it is not possible to obtain the highest sales,

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as with fixed catalytic converters. For this G-round are fixed catalysts according to the invention are preferred. The reactor is preferably designed so that it is from series consists of small diameter tubes connected to the catalyst are filled. The tubes are expediently enclosed in a jacket in a 2 form of a bundle, in which and through which a liquid or gaseous medium can be introduced for the removal and supply of heat. This embodiment is conveniently used to improve temperature control in the tubes of the reactor, whereby the otherwise frequently occurring coking of the methanol is avoided, otherwise easily with insufficient temperature control so-called "hot spots" can develop in the reaction zone.

The invention can be conveniently illustrated using the apparatus shown in the accompanying drawings carry out.

A reactor (1) is provided with a jacket (2) through which a plurality of tubes (3) of small diameter extend. The tubes (3) end at each end of the jacket (2), whereby they go through a wall (4) and thereby delimit two zones within the jacket. A zone forms the interior of the Tubes, and the other zone extends between the exterior of the tube walls and the interior of the jacket (2). A headboard (5) is arranged at each end of the jacket (2) so as to prevent the flow of liquid and / or gas with the inner Zone to allow the tubes from one end of the jacket to the other. At the height of the end of the shell (2) are Rohransohlüsse (6) provided to prevent traffic in and through the zone between the inside of the cladding wall and the outside

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the pipe walls is to allow the coolant to pass through allow. Alternatively, several such openings can be arranged in the jacket wall and also guide plates in this zone to determine the direction for the flow of the medium in this zone. Are in connection with the head parts (5) Supply lines (9) and (10) for the starting materials and one or more discharge lines for the products that come from the Come inside the pipes. The tubes shown are filled with the catalyst.

In one approach, methanol and preferably anhydrous hydrogen chloride feedstock is fed into the evaporator (7) and (8) introduced where the methanol and hydrogen chloride be evaporated in each case. The starting materials vaporized in this way are then fed in the desired ratio to the head part · (5) through the feed lines (9) and (10), where they then come into contact with the catalyst in the tubes (3). The exothermic heat of reaction is transmitted through the heat transfer medium added, which flows through the reactor between the jacket and the outer tube walls. The one from the discharge line the products emerging from the head part (5) are condensed, divided and purified.

example 1

Using the apparatus shown in the figure, work is carried out under the following conditions: A gamma-alumina (F-I) in pieces from 0.63 to 1.27 cm (1/4 "to 1/2") is used as the catalyst and is placed at a height of about 6 m (20 feet) in the reactor. the The maximum temperature of the reactor is given in the following table as well as the inlet and outlet pressure «>,

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19070

- ■ 5 -

The feed stream consisted of dry methanol and dry hydrogen chloride. The turnover or conversion of the Methanol, hydrogen chloride and the yield of methyl chloride is given for each attempt.

Raw materials
(kg mole / day)
MeOH HCl pressure
(Atm)
on off 3.4 temperature conversion
MeOH HCl 94.6 yield
CH ₃ Cl A 2.27 2.39 3.6 2.36 308 98.1 85.3 - B 2.27 2.39 2.7 2.36 332 98.6 93.7 97.8 C 2.4 2.3 2.7 4.4 295 94.7 96.6 - D 2.5 2.28 4.5 309 - Example 2

Following the procedure of Example 1, the following values were obtained: the formation of by-products depending on the different molar ratio of the starting materials will be shown.

Total mole Molar ratio s Pressure· fo CH-OCH ,, Raw materials CH3OH / HC1 (Atm) in the product A 14.7 1.0 / 1.1 4.4 0.19 B 14.7 1.0 / 1.0 4.4 0.84 C 14.7 1.1 / 1.0 4.4 1.72 Example 3

The procedure of Example 1 was followed, the influence of the pressure on the formation of by-products was investigated. The MeOH / HCl molar ratio was 1.0 / 1.1.

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Total mole pressure MeOH 56 5 * CH ^ OCH, Raw materials (Atm) conversion in the product A 10.5 2.36 97.2. 0.64 B 10.5 3.4 .. 98.1 0.39 C 14.7 4.4 —— 0.19 Example 4

The procedure of Example 1 was followed to show the influence of temperature on the formation of the by-product , a 10 ^ iger excess of each starting material being used in various experiments.

Total mole 10.5 Molar ratio pressure Max. 56 CH, OCH, Raw materials 10.5 MeOH / HCl (Atm) Kr in the product A. 10.5 1.0 / 1.1 2.36 300 0.64 B. 10.5 1.0 / 1.1 2.36 332 0.43 C. 10.5 1.0 / 1.1 2, -56 360 0.29 D. Example 5 1.1 / 1.0 4.4 309 2.07 E. 1.1 / 1.0 4.4 334 2.44

A 32% aqueous hydrochloric acid was used instead of dry hydrogen chloride , the following results being obtained by changing the ratio of the starting materials and the temperature according to the table " The catalyst used was either a coarse-grained or a finer-grained one (4 or 6 mesh) gamma aluminum oxide used "The only effect that was observed was the increased pressure drop with the finer-grain catalyst used"

Ö09S

Raw materials Molver Mittlo pressure floor the end Pure (kg mol / a? ag) ratio Eempo head prey Ness CH-OH HCl * ch ₅ oh / hci . ⁰ C 1.68 * A 1.96 1.87 1.05 289 2.56 1.61 92.4 96.1 B 1.77 2.1 0.84-3 293 3.07 1.65 92.9 99.0 C 2.018 2.02 0.991 292 3.21 89.3 99.0

* As percent by weight aqueous hydrochloric acid.

The product yield in the table above is an overall yield for the methyl chloride obtained from the methanol starting material

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Claims (6)

Claims; ΎΛ Improved process for the production of methyl chloride by reacting methanol and hydrogen chloride in the presence of a gamma-aluminum oxide catalyst at elevated (temperature and a pressure of at least one atmosphere, characterized in that a mixture of 0.75 to 1.1 molar proportions Methanol is brought into contact with the catalyst at a temperature between 150 ° C and 500 ° C for each mole fraction of hydrogen chloride. 2. The method according to claim 1, characterized in that the G
is brought into contact up to 360 ° C. " Mixing with the catalyst at a temperature of 289 ° 0 3. The method according to claims 1 or 2, characterized in that that 0.95 to 1 molar part of methanol is used per one molar part of hydrogen chloride. 4. Process according to Claims 1 to 3> characterized in that the mixture of starting materials used is essentially is anhydrous. 5. The method according to claims 1 to 3> characterized in that that the hydrogen chloride used is an aqueous solution which contains at least 15% by weight of hydrogen chloride. 6. The method according to claims 1 to 5, characterized in that that a pressure of 1.5 "to 10 atmospheres to the touch the mixture of the starting materials with the catalyst upright is received " 909637/1549