CS248970B1 - Process of producing phosphorous thiochloride - Google Patents

Abstract

The solution relates to the production of phosphorus thiochloride by reacting phosphorus trichloride with sulfur. The method is carried out in a batch system in the presence of activated carbon. In the first batch, an alkali metal and/or alkaline earth metal hydroxide, oxide, sulfide, polysulfide or a mixture thereof is added to molten sulfur. Phosphorus thiochloride is separated from the reaction mixture by rectification. At least 1 batch is made with ash-containing sulfur and subsequent batches are made with ash-free sulfur. The reaction of phosphorus trichloride with sulfur is carried out in the presence of a solid residue after the production of CaSx by reaction with an aqueous solution of calcium hydroxide and sulfur, which contains CaSx, CaS, Ca(OH)2, sulfur, CaSO3, CaSO4 and CaS2O3. The invention can be used in the production of PSC13, which has extensive use, e.g. for the production of organophosphates.

Description

The present invention relates to the production of phosphorous thiochloride by reacting phosphorus trichloride with sulfur.

The process is carried out in a batch system in the presence of activated carbon. In the first batch, alkali metal and / or alkaline earth metal hydroxide, oxide, sulfide, polysulfide or a mixture thereof is added to the molten sulfur.

The phosphorous thiochloride is separated from the reaction mixture by rectification. At least 1 batch is made with ash-containing sulfur and subsequently made with ash-free sulfur. The reaction of phosphorus trichloride with sulfur is carried out in the presence of a solid residue after CaS _x production by reaction with an aqueous solution of calcium hydroxide and sulfur containing CaS _x , CaS, Ca (OH) 2, sulfur, CaSO 3, CaSO 4 and CaS 2 O 3.

The invention can be used in the manufacture of PSC13 having extensive application, e.g. for the production of organophosphates.

The invention relates to the production of phosphorous thiochloride by reacting phosphorus trichloride with sulfur.

Phosphorous thiochloride can be prepared in several ways. The reaction between phosphorus pentachloride and hydrogen sulfide (1) is described by G. S. Seraltus, Am. Chem. Phys. 42, 25 (1829), and W. Rabston, J. Am. Chem. Soc. 50,258 (1928).

PC15 -I- HZS -> PSCD + 2 HC1

Another possible production method is the reaction of SOCl 2 with P2S5, or the reaction of FeCl 3 with P2S5 (2, 3) described by E. Glatzel, Chem. Ber. 23, 37 (1890). Also known is the reaction of phosphorus pentasulfide with phosphorus pentachloride (4) described by T. E. Thorje, Chem. News 24,135 (1871).

SOCI2 4- 2 P2S5-4 PSCD + 3 SO2 4- 9 S (2)

FeCD + 2 P2S5 -> 3 FeCl2 4 - 3 FeS 4 - 4 PSCD (3)

P2S5 + 3 PC15-5 PSCD (4)

Of great industrial importance is the reaction of phosphorus trichloride with the sulfur (5) which I describe! e.g. L. Henry, Chem. Ber. 2, 638 (1869), A. Perotti, C.A. 55, 4223 f (1961). Activated carbon, or AlCl 3, is most often used as the catalyst for the reaction.

PC13 4- S -> PSCD

Catalysis with AlCl 3 is described, e.g. F. Knotrz Oster. Chem. Zeolung 50, 128, (1949), catalysis in the presence of Na 2 S 5, is described in USSR Pat. 77 103 (1949), U.S. Pat. 2 575 316, eventually brit. pat. 694 380.

In the aforementioned references, no attention is paid to the disintegration of impurities resulting from the reaction (5% of sulfur and polluting the reaction boiler and must be omitted after several batches).

The above drawbacks are overcome by the process for the production of phosphorous thiochloride, which consists in preparing phosphorous thiochloride by reacting PCD with molten sulfur in the presence of an activated carbon catalyst. PCl 3 is added to the mixture of molten sulfur and the reaction formed by the PSCD gradually over a period of about 2 hours. The reaction is preferably carried out at the boiling point of the reaction mixture. The PSCI3 and PCD vapors condense in the condenser and the liquid returns to the reaction mixture. Once the selected degree of PCI3 to PSCls has been reached, which can be well determined by temperature, the technical PSC1.3 is distilled off. The distillate obtained also contains PCl3 which has a lower boiling point than PSCl3, the more volatile it is. Only PCD and molten sulfur are added to the next batch. It is preferred to leave a portion of the PSCD in the reaction boiler, thereby increasing the boiling point of the reaction mixture and hence the reaction rate. The alkali metal or alkaline earth metal hydroxide, oxide, sulfide, polysulfide, carbonate, or a mixture thereof, is added to the molten sulfur, preferably in the first batch. The molten sulfur does not contain ash or has reduced the ash content by filtration.

Preferably, the obtained phosphorous thiochloride is obtained by rectification and is removed from the bottom of the rectification column.

It is preferable to make at least a batch 1 of conventional molten sulfur containing ash and to make subsequent batches with ash-free sulfur or reduced-ash sulfur by filtration.

In the first batch, solid waste resulting from the reaction of the aqueous Ca (01-1) 2 solution with the sulfur and filtration of the technical CaS _x solution is added to the molten sulfur. This waste contains CaS _x , CaS, Ca (OH) 2, CaSO 3, CaSO 2, sulfur and impurities from Ca (OH) 2.

According to the process according to the invention, PSCI3 can be produced by reacting PCD and sulfur indefinitely, without inorganic sulfur impurities (ash) accumulating in the reaction boiler, which hitherto limited production, while after some time impurities together with unreacted PCD, PSCD, activated carbon had to be removed. and the whole cycle was repeated. The resulting waste is difficult to process because of its composition, or its storage in chemical waste dumps is problematic because it reacts with air humidity to form hydrogen chloride, which contaminates the environment. The process of the invention removes these shortcomings, thereby improving the environment and increasing the availability of raw materials. The reaction of PCl 2 with sulfur in the presence of activated carbon in the first batches is more difficult to start, which is removed by addition to the oxide, hydroxide, sulfide, polysulfide, alkali metal carbonate, or alkaline earth. Rectification yields high purity PSCI3.

Example 1

In a three-necked flask equipped with a thermometer, a separating funnel for the addition of PCD, a reflux condenser and an electromagnetic stirrer, was added 35 g of sulfur containing 0.42 percent by weight. 100 ml of PSCl3 and 13 g of powdered activated carbon were added. 150 g of technical PCI3 were added dropwise over two hours. The mixture was kept under gentle reflux at gentle boiling. After the addition of PCD, the mixture was kept at low boiling for 3 hours. Then 115 ml of technical PSCD containing 89.2 wt. PSCD.

In the second batch, 35 g of sulfur and 150 g of PCD were added and proceeded as in the first batch. The procedure was repeated 3 times and the following results were obtained:

89.6; 91.2; 93.4; 91.9 wt. PSC13.

For further batches, ash-free sulfur was metered by filtration. The following results were obtained:

92.8; 91.9; 93.4; 94.2; 93.8 wt. PSC13.

In the next batch, ash free (obtained from Claus furnace) was used. The yield was 93.9%. PSCl 3.

Example 1 a d 2

The first batch was carried out according to Example 1 except that 0.5 g of technical NaOH (solid) was added to the molten sulfur, and the sulfur was heated at about 140 ° C for 1 hour. The first five batches achieved:

91.3; 93.6; 94.2; 93.9; 94.4 wt. PSC13. Example 3

The procedure of Example 2 was followed except that NaOH, CaO was added and the technical PSCl3 was rectified upon completion of the reaction. 115 ml of PSCI3 at a concentration of 98.9% by weight were removed from the distillation residue. PSC13. The distillate was used as template for the second batch.

Example 4

The procedure of Example 3 was followed except that CaS was used instead of CaO. The distillation residue contained 97.9 wt. PSC13. Example 5

The procedure of Example 3 was followed except that technical K 2 CO 3 was used instead of CaO. The distillation residue contained 98.2 wt. PSC13.

Example 6

The procedure of Example 3 was followed except that solid waste was used instead of CaO after CaS _x production by reacting an aqueous Ca (OH) 2 solution with sulfur and filtering out the CaS _x solution. The solid waste had the following weight concentration:

Time. 7.3%, Ca (OH) 2 14.5%, sulfur 13.2%, CaSO 3 21.4%, CaS 2 O 3 6.5%, CaCO 3 5.2%, CaS 21.5%.

The distillation residue contained 98.9 wt. PSC13.

The invention can be used in the manufacture of technical PSC13, which is most commonly used for the production of organic phosphorus compounds used as insecticides. Embodiments of the invention are simple and easy to implement on the prior art. Cleaner PSCI3 can be obtained, practically it is possible to prolong the cycle of catalyst replacement used to the reaction boiler repair cycle. After the reaction, inorganic sulfur fumes were not left in the reaction boiler, so there is no need to release the batch after a certain number of batches.

This improves the yields and makes the machinery more usable. Problems around the discharge of the catalyst with unreacted fractions from the reaction boiler and its disposal, or storage, are eliminated.

In the production of PSCI3 it is possible to use solid waste as a sulphide source resulting from the production of CaS _x , which is currently not used, and there are problems with its storage or disposal. In addition to the catalytic effects of the present inorganic compounds, the sulfur present in the waste can also be used for the production of PSCI3.

Claims (4)

248970 várke. The procedure was repeated 3 times and the following results were obtained: 89.6; 91.2; 93.4; 91.9 wt. PSC13. In the next batches, sulfur ash was removed by filtration. The following results were obtained: 92.8; 91.9; 93.4; 94.2; 93.8 wt. PSCK In a further batch, sulfur was used which did not contain ash (obtained from Claus pellets). The yield was 93.9% by weight. PSCI3. EXAMPLE 2 The procedure of Example 1 was followed, except that 0.5 g of technical NaOH (solid) was added to the molten sulfur, and the sulfur was heated to about 140 ° C for 1 hour. Next, the procedure of Example 1 was followed. In the first batches: 91.3; 93.6; 94.2; 93.9; 94.4 wt. EXAMPLE 3 The procedure of Example 2 was followed with the difference that instead of NaOH, CaOa was added after completion of the reaction, the technical PSC13 was subjected to rectification. 115 ml of PSCI3 with a concentration of 98.9% by weight were removed from the distillation residue. PSC13. The distillate was used as a second batch. Example 4 Example 3 was followed with the difference that CaS was used instead of CaO. The distillation residue contained 97.9 wt. Example 5 The procedure of Example 3 was followed except that K 2 CO 3 was used instead of CaO. The distillation residue contained 98.2 wt. Example 6 The procedure of Example 3 was followed with the difference that the solid waste was used instead of CaO after the production of CaSx by reaction of the aqueous solution of Ca (OH) 2 with sulfur and filtration of the CaSx solution. The solid waste had the following concentration: CaS. 7.3? / O, Ca (OH) 2 14.5%, sulfur 13.2%, CaSO3 21.4%, CaS2O3 6.5%, CaCO3 5.2%, CaS 21.5%. The distillation residue contained 98.9% by weight of PSCK The invention can be used in the production of PSC13, which is most commonly used to produce organic phosphorus compounds that are used as insecticides. The conversion of the invention is undemanding and easy to implement in the prior art. By obtaining purer PSCI3, it is practically possible to overcome the cycle of replacement of the used catalyst to the repair cycle of the reaction boiler. After the reaction, inorganic sulfur compounds were not left in the reaction mixture, which means that it is not necessary to discharge them after a certain number of times. This improves the yields and achieves a better utilization of the machinery. The problems of discharging the catalyst with unreacted portions of the reaction vessel and around its disposal are eliminated, and storage is avoided. In the production of PSCI3, solid waste can be used as the sulphide source resulting from the production of CaSx, which is currently not used and has problems with its storage, possibly disposal. In addition to the catalytic effects of the inorganic compounds present, sulfur can also be used in the production of PSCI3. PREDMEI A process for producing phosphorous thiochloride by reacting phosphorous trichloride with sulfur in the presence of activated carbon at the temperature of the reaction mixture, whereupon phosphorous thiochloride with unreacted phosphorous trichloride is distilled off, followed by the addition of chlorine. phosphorous triside and sulfur, characterized in that the first batch is added to the sulfur, preferably in the form of a melt, hydroxide, oxide, sulfide or polysulfide of an alkali metal or alkaline earth metal, or a mixture thereof, preferably molten sulfur it is free of polarity or the ash content is reduced by filtration. 2. Process according to claim 1, characterized in that the phosphorus pentachloride is separated from the phosphorus trichloride by rectification. 3. A process as claimed in claim 1, wherein at least one batch is made with molten sulfur containing ash and subsequently made with sulfur-free sulfur or sulfur-reduced sulfur. 4. A process as claimed in claim 1, wherein, in a first batch, a solid residue is obtained after the CaS production (by reacting a calcium hydroxide aqueous solution containing CaSx, CaS, Ca (OH) 2, sulfur, CaSO3, CaSO4). and OaS2O3.