PROCESS FOR PRODUCING METHYLDICHLOROPHOSPHANE

Abstract

The present invention primarily relates to a process for producing methyldichlorophosphane (MDP) by reaction of methane with PCl.sub.3 (phosphorus trichloride) in the presence of a catalytically active amount of a compound of formula SO.sub.xCl.sub.2, wherein the index x may take the value 1 (SOCl.sub.2, thionyl chloride) or 2 (SO.sub.2Cl.sub.2, sulphuryl chloride). The present invention further relates to particular mixtures that are particularly suitable for producing methyldichlorophosphane (MDP) in the context of the process according to the invention/that are formed when carrying out a process according to the invention.

Claims

1. A process for producing methyldichlorophosphane (MDP) by reaction of methane (CH.sub.4) with phosphorus trichloride (PCl.sub.3), wherein the reaction is carried out in the presence of a compound of formula SO.sub.xCl.sub.2, wherein x is 1 or 2.

2. A process according to claim 1, wherein the reaction is carried out in the presence of a catalytically active amount of SOCl.sub.2 and/or SO.sub.2Cl.sub.2.

3. A process according to claim 1, wherein the total amount of SO.sub.xCl.sub.2 is in the range from 0.1 to 10 mol % based on the amount of PCl.sub.3 employed.

4. A process according to claim 1, wherein the total amount of SO.sub.xCl.sub.2 is in the range from 0.5 to 9 mol % based on the amount of PCl.sub.3 employed.

5. A process according to claim 1, wherein the total amount of SO.sub.xCl.sub.2 is in the range from 2 to 8 mol % based on the amount of PCl.sub.3 employed.

6. A process according to claim 1, wherein the total amount of SO.sub.xCl.sub.2 is in the range from 3 to 7 mol % based on the amount of PCl.sub.3 employed.

7. A process according to claim 1, wherein the molar ratio of CH.sub.4 to PCl.sub.3 is in the range from 12:1 to 2:1.

8. A process according to claim 1, wherein the molar ratio of CH.sub.4 to PCl.sub.3 is in the range from 10:1 to 3:1.

9. A process according to claim 1, wherein the molar ratio of CH.sub.4 to PCl.sub.3 is in the range from 8:1 to 4:1.

10. A process according to claim 1, wherein the reaction is carried out at a temperature in the range from 400° C. to 750° C.

11. A process according to claim 1, wherein the reaction of CH.sub.4 and PCl.sub.3 to afford MDP is effected in a gas-phase reaction.

12. A product comprising a compound of formula SO.sub.xCl.sub.2, wherein x is 1 or 2, for producing methyldichlorophosphane (MDP).

13. A mixture comprising, or consisting essentially of or consisting of (i) PCl.sub.3, and (ii) SO.sub.xCl.sub.2, wherein x has the value 1 or 2, wherein the total amount of constituent (ii) SO.sub.xCl.sub.2, based on the amount of constituent (i) PCl.sub.3 employed, is optionally equal to the total amount defined in claim 3.

14. A mixture comprising, or consisting essentially of or consisting of (i) PCl.sub.3, (ii) SO.sub.xCl.sub.2, wherein x has the value 1 or 2, and (iii) CH.sub.4, wherein the total amount of constituent (ii) SO.sub.xCl.sub.2, based on the amount of constituent (i) PCl.sub.3 employed, is optionally equal to the total amount defined in claim 3, and/or the molar ratio of constituent (iii) CH.sub.4 and constituent (i) PCl.sub.3 is optionally equal to the ratio in the range from 12:1 to 2:1.

15. A mixture comprising, or consisting essentially of or consisting of (i) PCl.sub.3, (ii) SO.sub.xCl.sub.2, wherein x has the value 1 or 2, (iii) CH.sub.4, and (iv) MDP (methyldichlorophosphane).

Description

EXAMPLES

[0058] Methods of measurement:

[0059] Hewlett Packard gas chromatograph, column: Zebron ZB-624, 30 m×0.53 mm, 3 μm, He, 20:1 split ratio.

[0060] Detector: WLD, injection volume: 10 μl, 60° C., 5 min isothermal, 10° C./min, 230° C.

[0061] Rf (PCl.sub.3): 11.13 min, Rf (MDP): 11.92 min.

Example 1

[0062] A quartz tube reactor heated to 500° C. and having a diameter of 9 mm and a length of 170 mm was charged with 7.91 dm.sup.3/h of methane and 1.32 dm.sup.3/h of PCl.sub.3 and the volumetric ratio of CH.sub.4:PCl.sub.3 was therefore 6:1 (v/v). Dissolved in this PCl.sub.3 were 5 mol %, based on the amount of PCl.sub.3 employed, of SOCl.sub.2 (thionyl chloride) as catalyst. The liquid stream of the PCl.sub.3 and SOCl.sub.2 mixture were passed over a preevaporator heated to 250° C. prior to introduction into the reactor. A sample from the resulting product gas stream was conducted via condensation into a bypass cooled to −78° C. and subsequently analysed by gas chromatography (GC). The yield of MDP, based on the amount of PCl.sub.3 employed, is reported in Table 1 which follows.

Example 2

[0063] The production of methyldichlorophosphane (MDP) was carried out as per Example 1 with the temperature set to 550° C.

Example 3

[0064] The production of methyldichlorophosphane (MDP) was carried out as per Example 1 with the temperature set to 600° C.

Example 4

[0065] The production of methyldichlorophosphane (MDP) was carried out as per Example 1 with 5 mol %, based on the amount of PCl.sub.3 employed, of SO.sub.2Cl.sub.2 (sulfuryl chloride) being used as catalyst.

Example 5

[0066] The production of methyldichlorophosphane (MDP) was carried out as per Example 4 with the temperature set to 550° C.

Example 6

[0067] The production of methyldichlorophosphane (MDP) was carried out as per Example 4 with the temperature set to 600° C.

[0068] The yield of MDP obtained, in each case based on the amount of PCl.sub.3 employed, is reported in Table 1 which follows.

TABLE-US-00001 TABLE 1 Results of MDP production as per Examples 1 to 6 Example Catalyst Temperature Yield of MDP 1 SOCl.sub.2 500° C. 6.6% 2 SOCl.sub.2 550° C. 11.3% 3 SOCl.sub.2 600° C. 17.1% 4 SO.sub.2Cl.sub.2 500° C. 6.4% 5 SO.sub.2Cl.sub.2 550° C. 14.6% 6 SO.sub.2Cl.sub.2 600° C. 24.3%

[0069] Comparative tests with CCl.sub.4:

[0070] Comparative examples analogous to Examples 1 to 6 were carried out, wherein methane and PCl.sub.3 were reacted to afford MDP under the reaction conditions referred to in Examples 1 to 6 in the presence of CCl.sub.4 instead of SOCl.sub.2/SO.sub.2Cl.sub.2. The yields of MDP achieved in the presence of CCl.sub.4 were comparable with those achieved with SO.sub.2Cl.sub.2 in each of Examples 4 to 6.