Patent Application
20170313731
The present invention primarily relates to a process for producing methyldichlorophosphane (MDP) by reaction of methane with PCl3 (phosphorus trichloride) in the presence of a catalytically active amount of a compound of formula SOxCl2, wherein the index x may take the value 1 (SOCl2, thionyl chloride) or 2 (SO2Cl2, 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.
Processes for producing methyldichlorophosphane (CH3PCl2) or structurally similar compounds are known from the prior art.
EP 0999216 A2 describes a process for producing aliphatic alkyldihalophosphanes by reaction of an aliphatic hydrocarbon with a phosphorus trihalide, wherein the reaction is initiated photochemically with a UV excimer radiation source.
U.S. Pat. No. 2,137,792 relates to the reaction of alkanes having more than 5 carbon atoms with phosphorus trichloride using aluminium trichloride to afford the corresponding alkyldihalophosphane-aluminium trichloride complexes from which the corresponding alkyldihalophosphane may subsequently be liberated.
U.S. Pat. No. 3,210,418 describes the synthesis of alkyldihalophosphanes by reaction of alkanes with phosphorus trihalides in the presence of catalytic amounts of atmospheric oxygen as an initiator.
U.S. Pat. No. 3,709,932 describes a process for conversion of alkanes with phosphorus trihalides to afford alkyldihalophosphanes in the presence of catalytic amounts of phosgene.
U.S. Pat. No. 3,974,217 discloses a process for synthesizing substituted phenylphosphorus dihalides by reaction of substituted phenylene with phosphorus trihalides in the presence of catalytic amounts of tin tetrachloride or titanium tetrachloride.
U.S. Pat. No. 4,101,573 and DE 2629299 describe a process for producing methyldichlorophosphane by reaction of methane with phosphorus trichloride in the presence of 2 to 7 mol % of carbon tetrachloride based on the employed phosphorus trichloride, wherein at constant residence times of 0.1 to 0.9 seconds the carbon tetrachloride employed is reacted to an extent of 50% to 80% by varying the reaction temperature between 550° C. and 650° C.
J. Org. Chem. 1974, 39, 1303-1306 describes the free-radical chlorination of alkanes with thionyl chloride.
EP 0082350 A1 relates to the production of methyldichlorophosphane by reaction of methane with phosphorus trichloride in the presence of 2 to 7 mol % of carbon tetrachloride based on the employed phosphorus trichloride at temperatures of 500° C. to 650° C. and a residence time of 0.1 to 0.9 seconds, wherein the reaction is carried out at a pressure of 2 to 10 bar and the amount of carbon tetrachloride added is reduced with increasing pressure.
The recovery and purification of methyldichlorophosphane from reaction mixtures resulting from reaction of methane with phosphorus trichloride in the presence of carbon tetrachloride is described in U.S. Pat. No. 4,101,299 for example.
Production of MDP from PCl3 and methane (CH4) via a homogeneous gas-phase reaction often employs carbon tetrachloride (CCl4) as catalyst. The use of CCl4 has several disadvantages: CCl4 is highly toxic and a greenhouse gas and its use in the production of MOP results in the formation of deposits in the reactor and necessitates regular cleaning of the reactor.
It was a primary object of the present invention to find an alternative to the use of carbon tetrachloride in the process for producing MDP from PCl3 and methane.
This alternative process should preferably make it possible to avoid some if not all of the abovedescribed disadvantages associated with the use of carbon tetrachloride. This alternative process shall further make it possible to achieve yields of MDP that are comparable or improved compared to the process for producing MDP in the presence of carbon tetrachloride.
This object is achieved in accordance with the invention by the use of SOCl2 (thionyl chloride)/SO2Cl2 (sulphuryl chloride) in the reaction of methane with phosphorus trichloride.
The invention thus primarily relates to a process for producing methyldichlorophosphane by reaction of methane with phosphorus trichloride, characterized in that the reaction is carried out in the presence of a compound of formula SOxCl2, wherein x is 1 or 2.
The process according to the invention may be depicted schematically as follows, wherein the index x may take the values 1 (one) or 2 (two).
The process according to the invention is preferably carried out in the presence of a catalytically active amount of a compound of formula SOxCl2, wherein x is 1 or 2.
The process according to the invention is preferably carried out in the presence of a catalytically active amount of thionyl chloride and/or sulphuryl chloride.
In the process according to the invention the total amount of SOxCl2 is preferably in the range from 0.1 to 10 mol %, by preference in the range from 0.5 to 9 mol %, more preferably in the range from 1 to 8 mol %, particularly preferably in the range from 2 to 8 mol % and very particularly preferably in the range from 3 to 7 mol % in each case based on the amount of PCl3 employed.
The process according to the invention is preferably carried out at a temperature in the range from 400° C. to 750° C., by preference at a temperature in the range from 420° C. to 700° C., particularly preferably at a temperature in the range from 450° C. to 650° C.
In the process according to the invention the molar ratio (mol/mol) of CH4 to PCl3 is preferably in the range from 12:1 to 2:1, preferably in the range from 10:1 to 3:1 and particularly preferably in the range from 8:1 to 4:1.
The process according to the invention is preferably carried out at a reaction pressure in the range from 500 mbar and 25 bar, by preference at a reaction pressure in the range from 700 mbar and 12 bar, more preferably at a reaction pressure in the range from 900 mbar and 10 bar.
The process according to the invention is preferably carried out such that the reaction of CH4 and PCl3 to afford MDP is effected in a gas-phase reaction.
The process according to the invention is preferably carried out such that a homogeneous mixture comprising CH4, PCl3 and SOxCl2 is reacted to afford MDP in a gas-phase reaction.
The average residence time of the reaction constituents CH4, PCl3 and SOxCl2, preferably of the homogeneous mixture of CH4, PCl3 and SOxCl2, in the reaction space is preferably in the range from 0.05 to 60 seconds, by preference in the range from 0.1 to 10 seconds, more preferably in the range from 0.5 to 5 seconds.
The process according to the invention is preferably carried out such that CH4, PCl3 and SOxCl2 are reacted in a flow tube preferably in the amounts (ratios) identified as preferable/particularly preferable hereinabove or hereinbelow.
Provided that CH4, PCl3 and SOxCl2 are reacted in a flow tube, said flow tube preferably has a diameter of at least 5 mm, by preference a diameter of at least 8 mm.
Provided that CH4, PCl3 and SOxCl2 are reacted in a flow tube, said flow tube preferably has a length of at least 10 cm, by preference a length of at least 15 cm.
Provided that CH4, PCl3 and SOxCl2 are reacted in a flow tube, in a further preferred embodiment said flow tube preferably has a length of at least 100 cm, by preference a length of at least 150 cm.
The process according to the invention preferably employs SO2Cl2 (sulfuryl chloride) or a mixture of SO2Cl2 (sulfuryl chloride) and SOCl2 (thionyl chloride) as catalyst since the use of SO2Cl2 (sulfuryl chloride) in the process according to the invention makes it possible to achieve still higher yields of methyldichlorophosphane (MDP).
The process according to the invention is preferably carried out such that it employs no catalytically active amounts of elemental oxygen (O2), of elemental chlorine (Cl2), of phosgene (COCl2), of carbon tetrachloride (CCl4), of nitrogen oxides or of chlorohydrocarbons and preferably uses no UV excimer radiation source either.
The process according to the invention employs SOCl2 (thionyl chloride) and/or SO2Cl2 (sulfuryl chloride) as catalysts and preferably employs no active amount of any further catalyst and by preference employs no further catalysts and uses no UV excimer radiation source.
In a further aspect the present invention relates to the use of a compound of formula SOxCl2, wherein x is 1 or 2, for producing methyldichlorophosphane (MDP), in particular in one of the embodiments of the process according to the invention for producing methyldichlorophosphane (MDP) which have been identified as preferable.
In a further aspect the present invention relates to mixtures comprising, consisting essentially of or consisting of
(i) PCl3,
and
(ii) SOxCl2, wherein x has the value 1 or 2,
wherein the total amount of constituent (ii) SOxCl2 is preferably in the range from 0.1 to 10 mol %, by preference in the range from 0.5 to 9 mol %, more preferably in the range from 1 to 8 mol %, particularly preferably in the range from 2 to 8 mol % and very particularly preferably in the range from 3 to 7 mol % in each case based on the amount of constituent (i) PCl3 employed.
An inventive mixture consisting essentially of (i) PCl3 and (ii) SOxCl2, wherein x has the value 1 or 2, preferably refers to a mixture in which the sum of the constituents (i) and (ii) totals at least 85 wt %, preferably totals at least 90 wt % and particularly preferably totals at least 95 wt % in each case based on the overall weight of the mixture.
In a further aspect the present invention relates to mixtures comprising, consisting essentially of or consisting of
(i) PCl3,
(ii) SOxCl2, wherein x has the value 1 or 2,
and
(iii) CH4,
wherein
the molar ratio (mol/mol) of constituent (iii) CH4 to constituent (i) PCl3 is preferably in the range from 12:1 to 2:1, preferably in the range from 10:1 to 3:1 and particularly preferably in the range from 8:1 to 4:1.
It is preferable when the total amount of constituent (ii) SOxCl2 is preferably in the range from 0.1 to 10 mol %, by preference in the range from 0.5 to 9 mol %, more preferably in the range from 1 to 8 mol %, particularly preferably in the range from 2 to 8 mol % and very particularly preferably in the range from 3 to 7 mol % in each case based on the amount of constituent (i) PCl3 employed.
An inventive mixture consisting essentially of (i) PCl3, (ii) SOxCl2, wherein x has the value 1 or 2, and (iii) CH4 preferably refers to a mixture in which the sum of the constituents (i), (ii) and (iii) totals at least 90 wt %, preferably totals at least 95 wt % and particularly preferably totals at least 98 wt % in each case based on the overall weight of the mixture.
In a further aspect the present invention relates to mixtures comprising, consisting essentially of or consisting of
(i) PCl3,
(ii) SOxCl2, wherein x has the value 1 or 2,
(iii) CH4,
and
(iv) MDP (methyldichlorophosphane).
An inventive mixture consisting essentially of (i) PCl3, (ii) SOxCl2, wherein x has the value 1 or 2, (iii) CH4 and (iv) MDP (methyldichlorophosphane) preferably refers to a mixture in which the sum of the constituents (i), (ii), (iii) and (iv) totals at least 80 wt %, preferably totals at least 90 wt % and particularly preferably totals at least 95 wt % in each case based on the overall weight of the mixture.
The invention is elucidated by the examples which follow.
Methods of measurement:
Hewlett Packard gas chromatograph, column: Zebron ZB-624, 30 m×0.53 mm, 3 μm, He, 20:1 split ratio.
Detector: WLD, injection volume: 10 μl, 60° C., 5 min isothermal, 10° C./min, 230° C.
Rf (PCl3): 11.13 min, Rf (MDP): 11.92 min.
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 dm3/h of methane and 1.32 dm3/h of PCl3 and the volumetric ratio of CH4:PCl3 was therefore 6:1 (v/v). Dissolved in this PCl3 were 5 mol %, based on the amount of PCl3 employed, of SOCl2 (thionyl chloride) as catalyst. The liquid stream of the PCl3 and SOCl2 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 PCl3 employed, is reported in Table 1 which follows.
The production of methyldichlorophosphane (MDP) was carried out as per Example 1 with the temperature set to 550° C.
The production of methyldichlorophosphane (MDP) was carried out as per Example 1 with the temperature set to 600° C.
The production of methyldichlorophosphane (MDP) was carried out as per Example 1 with 5 mol %, based on the amount of PCl3 employed, of SO2Cl2 (sulfuryl chloride) being used as catalyst.
The production of methyldichlorophosphane (MDP) was carried out as per Example 4 with the temperature set to 550° C.
The production of methyldichlorophosphane (MDP) was carried out as per Example 4 with the temperature set to 600° C.
The yield of MDP obtained, in each case based on the amount of PCl3 employed, is reported in Table 1 which follows.
Comparative tests with CCl4:
Comparative examples analogous to Examples 1 to 6 were carried out, wherein methane and PCl3 were reacted to afford MDP under the reaction conditions referred to in Examples 1 to 6 in the presence of CCl4 instead of SOCl2/SO2Cl2. The yields of MDP achieved in the presence of CCl4 were comparable with those achieved with SO2Cl2 in each of Examples 4 to 6.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14194201.1 | Nov 2014 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/076921 | 11/18/2015 | WO | 00 |
