United States Patent (19) 11 Patent Number: 4,889,661 Kleiner 45 Date of Patent: Dec. 26, 1989 (54) PROCESS FOR THE PREPARATION OF Kosolapoff, G. M. et al. Organic Phosphorus Compounds AROMATIC PHOSPHORUS-CHLORNE (1973) vol. 4 at p. 95. Wiley-Interscience, Publ. COMPOUNDS Kosolapoff, Gennady M. Organophosphorus Com 75 Inventor: Hans-Jerg Kleiner, pounds (1958), John Wiley & Sons, Publ. pp. 59-60. Kronberg/Taunus, Fed. Rep. of Primary Examiner-Paul J. Killos Germany Attorney, Agent, or Firm-Curtis, Morris & Safford 73) Assignee: Hoechst Aktiengesellschaft, 57 ABSTRACT Frankfurt am Main, Fed. Rep. of Aromatic phosphorus-chlorine compounds, especially Germany diphenylphosphinyl chloride (C6H5)2P(O)Cl, phenyl phosphonyl dichloride C6HsP(O)Cl2, dichlorophenyl 21 Appl. No.: 554,591 phosphine C6HsPCl2 and chlorodiphenylphosphine (C6H5)2PCl, and the corresponding sulfur analogs, are 22 Filed: Nov. 23, 1983 obtained by reaction of aromatic phosphorus com 30 Foreign Application Priority Data pounds, which contain oxygen or sulfur, of the formula I Nov. 27, 1982 DE Fed. Rep. of Germany ....... 324.4031 511 Int, C.'................................................ CO7C 5/02 52 U.S. C. .................................... 562/815; 562/818; 562/819 58) Field of Search ..................................... 260/543 P in which X=O or S, and m= 1, 2 or 3, with phosphorus 56) References Cited chlorine compounds of the formula II U.S. PATENT DOCUMENTS (C6H5)3P Cln (II) 3,244,745 4/1966 Toy et al. ........................ 260/543 P FOREIGN PATENT DOCUMENTS in which n=1, 2 or 3, at temperatures between about 0093420 4/1983 European Pat. Off. 330 and 700° C. Preferred starting materials are tri phenylphosphine oxide (C6H5)3PO and phosphorus OTHER PUBLICATIONS trichloride PCl3. Houben-Weyl Methoden der Organischen Chemie, Band The reaction products are mainly intermediates in a XII/1, (1963), Georg Thieme, Publ. Stuttgart. Organis variety of special areas, such as the pharmaceuticals, che Phosphorverbindungen, Pt. 1 K. Sasse at page 129. plant-protection, dye and polymer sectors. Derwent Abstracts 51,340 K/21, (Russian 943,243 dtd Jul. 15, 1982). 6 Claims, No Drawings 4,889,661 1. 2 phine oxides or sulfides in the following text-of the PROCESS FOR THE PREPARATION OF formula I: AROMATIC PHOSPHORUS-CHLORNE COMPOUNDS X (I) I Aromatic phosphorus-chlorine compounds, such as, for example, diphenylphosphinyl chloride (C6H5)2P (O)Cl, phenylphosphonyl dichloride C6HsP(O)Cl2, in which X=O or S, preferably=O and m=1, 2 or 3, phenylthiophosphonyl dichloride C6HsP(S)Cl2, di with phosphorus-chlorine compounds of the formula II chlorophenylphosphine C6HsPCl2, chlrodiphenylphos 10 phine (C6H5)2PCl, etc., are mainly intermediates in (C6H5)3-PCln (II) various special fields, such as the pharmaceuticals, plant-protection, dye and polymer sectors. in which n=1, 2 or 3, at temperatures between about These compounds can be prepared by a number of 330 and 700 C. known methods. Thus, for example, diphenylphosphi 15 The phosphine oxides and sulfides included in the nyl chloride (C6H5)2P(O)Cl can be obtained in a con formula I contain at least one phenyl radical bonded to ventional manner from diphenylphosphinic acid the phosphorus; the compounds are as follows: (C6H5)2P(O)OH which, in turn, is accessible by alkaline decomposition of triphenylphosphine oxide (C6H5)3PO; for X-O the latter (triphenylphosphine oxide) is an industrial 20 waste product which is produced in not inconsiderable when amounts, especially in the so-called Wittig reaction. m=3: triphenylphosphine oxide (C6H5)3P=O Phenylphosphonyl dichloride C6H5P(O)Cl2 can be when obtained, inter alia, by phosgenation of phenylphos m=2; diphenylphosphinyl chloride phonic diesters C6HsP(O)(OR)2, in which R= organic 25 radical; phenylphosphonic diesters are, in turn, accessi ble, for example, by reaction of bromobenzene with O trialkyl phosphites in the presence of nickel bromide. chor?spra Phenylthiophosphonyl dichloride C6HsP(S)Cl2 is Cl obtained, for example, by sulfuration, starting from 30 dichlorophenylphosphine C6H5PC12. when Dichlorophenylphosphine C6H5PCl2 and chlorodi phenylphosphine (C6H5)2PCl are produced, for exam m=1: phenylphosphonyl dichloride ple, by the method of K. Sommer (Zeitschrift fir anor ganische und allgemeine Chemie, 376 (1970) p. 39) to 35 O Cl gether by reaction of triphenylphosphine (C6H5)3P C6H5 / with phosphorus trichloride PCl3 at temperatures N around 280 C. under pressure, optionally with the C addition of AlCl3 as a catalyst. Moreover, it has already been proposed (Patent Application P 3,216,381.9-HOE for X=S 82/F 086) to prepare dichlorophenylphosphine and when chlorodiphenylphosphine by reacting triphenylphos m=3: triphenylphosphine sulfide (C6H5)3P=S phine and phosphorus trichloride at temperatures be when tween 320” and 700 C., the process advantageously m=2: diphenylthiophosphinyl chloride being carried out under elevated pressure in the temper 45 ature range between 320 and 500 C., and under normal pressure in the temperature range between about 500 and 700' C, Although at least some of the processes of the state of the art for the preparation of aromatic phosphorus-chlo 50 Cl rine compounds are quite useful processes (such as, in particular, that for the preparation of dichlorophenyl when phosphine and chlorodiphenylphosphine in accordance m=1: phenylthiophosphonyl dichloride with Patent Application P3,216,381.9-HOE 82/F 086), the starting materials necessary for them are not always 55 accessible easily and at low cost. With the object of improving the processes of the state of the art for the preparation of aromatic phos Cl phorus-chlorine compounds, especially in respect of the choice of starting materials which are easier to obtain Preferred compounds I are those with X=O (phos and of lower cost, it has now been found that this aim is phine oxides). A particularly preferred compound I is achieved by reacting triphenylphosphine oxide or sul triphenylphosphine oxide (C6H5)3PO; this compound is fide with phosphorus trichloride and reacting the pri an industrial waste product which is produced in con mary products resulting from this reaction. siderable quantity (particularly in the Wittig reaction). Thus the invention relates to a process for the prepa 65 The other compounds of the formula I with X=O ration of aromatic phosphorus-chlorine compounds and m=2 and m=1 can then be obtained, inter alia, by which comprises reacting aromatic phosphorus com the reaction according to the invention of triphenyl pounds which contain oxygen or sulfur-denoted phos phosphine oxide with phosphorus trichloride. 4,889,661 3 4. Triphenylphosphine sulfide (C6H5)3PS is accessible, for this. Lead, copper, silver and nickel compounds are for example, by sulfuration of triphenylphosphine in a preferred. known manner. The compounds of the formula I with The amount of catalyst is normally between about 0.1 X=S and m=2 and m=1 can be obtained in a manner and 2% by weight, preferably between about 0.3 and analogous to the corresponding oxygen compounds, for 5 0.8% by weight, relative to the phosphine oxide or example, by the reaction according to the invention of sulfide of the formula I which is used. triphenylphosphine sulfide with phosphorus trichloride. Normally, the process according to the invention The phosphorus-chlorine compounds included in provides a mixture of various aromatic P-C compounds formula II are as follows: which can be separated by distillation. As a rule, the when n=3: phosphorus trichloride PCl3 10 when n=2: dichlorophenylphosphine C6HsPCl2 main products produced are the phosphorus derivatives when n=1: chlorodiphenylphosphine (C6H5)2PCl. formed from the phosphine oxides or sulfides of the The preferred compound II is phosphorus trichloride formula I by replacement of one and, when present, two PCl3; it is a known commercial product which is avail phenyl groups by chlorine, and the phosphorus com able in large quantities. For the reaction according to 15 pounds formed from the P-Cl compounds of the for the invention, it is advantageous to use the phosphorus mula II by replacement of a chlorine atom by the trichloride in the freshly distilled form. phenyl group: While the compounds of the formula II with n=2 and n=1 can, as mentioned in the introduction, be obtained, for example, by reaction of triphenylphosphine with 20 phosphorus trichloride, it is more favorable to prepare them from triphenylphosphine oxide and phosphorus trichloride in the manner according to the invention. In order to carry out the process according to the (X = O, S; m = 1,2,3) invention, the phosphine oxides or sulfides I and the phosphorus-chlorine compounds II are advantageously 25 employed in a molar ratio of about 1:1 to 4. However, excesses of, for example, compounds I and excesses of (C6H5)3-PCln (II) - G (C6H5)4-.PCln-1 compounds II above the molar ratio of, for example, 1:4 (n = 1,2,3) are likewise possible. In the lower part of the temperature range in the 30 In the preferred case where triphenylphosphine oxide process according to the invention-at about 330 to is used as starting compound I and phosphorus trichlo 500 C.-temperatures between about 360 and 460 C. ride is used as starting compound II, this means that the are preferred. main products formed are diphenylphosphinyl chloride, This process variant is preferably carried out under phenylphosphonyi dichloride and dichlorophenylphos superatmospheric pressure, in particular under the (au 35 phine: togenous) pressure set up in a closed reaction vessel O (between about 5 and 100 bar as a rule). I In this instance, the reaction time is always between (C6H5)2PCl about 1 and 80 hours, the shorter reaction times being Diphenylphosphinyl chloride advantageous at the higher temperatures and the longer reaction times at the lower temperatures. In the upper part of the temperature range in the O C6H5PCl2 process according to the invention-at about 500 to Phenylphosphonyl dichloride 700 C.-the preferred temperatures are between about 45 500' and 600 C.