3,287,388 United States Patent Office Patented Nov. 22, 1966 1. 2 carried out at a temperature of at least 20° C. and prefer 3,287,388 PROCESS FOR PREPARING ARYLFLUOROFOR ably above 100° C. At lower temperatures the reaction MATES AND ARYLFLUOROTHOLFORMATES proceeds very slowly, but at a slightly elevated tempera Karl O. Christe and Attila E. Paviath, Berkeley, Calif., as ture the completion of the reaction is enhanced. The signors to Stauffer Chemical Company, New York, temperature can be much higher depending on the nature N.Y., a corporation of Delaware of the arylchloroformate or arylchlorothiolformate and No Drawing. Filed Aug. 7, 1963, Ser. No. 300,638 the boiling point of the solvent, if one is used. The 1 Claim. (C. 260-455) preferred range is from about 50° to about 250° C. The reaction can be carried out with or without a sol This invention relates to a new and novel method for 10 vent. Either the arylchloroformate or arylchlorothiol preparing fluorine containing aromatic compounds. In formate may be used alone, or where the reaction may particular, it refers to a process for preparing the classes be enhanced by the presence of an inert solvent, for ex of fluorinated aromatic compounds, aromatic fluoro ample sodium fluoride in acetonitrile, a solvent may formates and aromatic fluorothiolformates by chlorine be used. - fluorine halogen exchange. This method can be used to 5 The reaction can be carried out at atmospheric pres prepare both the monocyclic and polycyclic arylfluoro sure under Substantially anhydrous conditions in conven formates or arylfluorothiolformates. They can be either tional glass laboratory equipment. The reactants are mono- or poly-fluoroformates or fluorothiolformates. brought into intimate contact with stirring and heated The aromatic nucleus can be either unsubstituted or sub if necessary. Normally the reaction can be completed stituted with such groups as halogen, alkyl, haloalkyl, 20 satisfactorily in at least 2 hours, and preferably from alkoxy, haloalkoxy and the like. 3 to 5 hours. Longer reaction times can be used and The arylchloroformates, which are well known, have are sometimes necessary when the arylchloroformate or been described frequently in the literature. Especially arylchlorothiolformate offers special resistance to fluori the preparation and chemical properties of phenylchloro nation by the fluoride being used. formate have been studied and described in the literature. 25 A convenient procedure for work up of the crude re The novel properties of the arylfluoroformates permits action product, if no solvent is used, is to extract the their use in a variety of applications. For example, they organic product with methylene chloride. Any other can be used as intermediates in preparing the correspond suitable inert solvent that can be easily removed may be ing fluoroaromatic compounds, as shown in our copend used instead. After removal of the low boiling extract ing application Serial No. 300,666, filed on even date 30 solvent, the remaining organic material can be easily dis herewith and now abandoned; as intermediates for or tilled in vacuo. If a solvent were used in the reaction ganic compounds useful in agricultural chemicals, the crude reaction product could be filtered first, then pharmaceuticals, as plasticizers, and in resins. the solvent removed by vacuum distillation. The puri The only reported preparation of phenylfluoroformate fication of the desired organic product can be done by was by Emeleus and Wood, J. Chem. Soc., 1948, 2183-8. 35 vacuum distillation in the usual manner. The preparation was described using carbonyl fluoride The following examples are illustrative of the with phenol in an autoclave. The yield of phenylfluoro invention. formate was not very high because of excessive diphenyl EXAMPLE I carbonate formation in the procedure used. A general object of the present invention is to provide 40 A mixture of 400 g. (2.5 moles) of phenylchloro a new process for preparing arylfluoroformates and formate and 110 g. (1.4 moles) of potassium bifluoride arylfluorothiolformates. was placed in a 500 ml. 4-neck flask fitted with a stirrer, A more specific object is provision of a process for thermometer, addition port and reflux condenser with preparing such arylfluoroformates and arylfluorothiol calcium chloride drying tube. No solvent was used in formates by a halogen exchange reaction which avoids this example. The mixture was stirred and electrically the use of pressure equipment and decreases the yield of heated to 100 C. for 3 hours. At the end of this time diarylcarbonate and diaryldithiolcarbonate formation. the entire mixture was extracted with methylene chloride. The invention can be carried out by contacting the cor The methylene chloride was removed on a rotating responding arylchloroformate or arylchlorothiolformate evaporator and the remaining organic material, impure of the desired arylfluoroformate or arylfluorothiolformate 50 phenylfluoroformate, was fractionally distilled in vacuo. with an inorganic fluoride of an element having an atomic The phenylfluoroformate distilled at a boiling point number from 11 to 83 inclusive, or hydrofluoric acid, and of 47.1° C. at 7 mm. Hg (153 C. at 760 mm. Hg). isolating the arylfluoroformate or arylfluorothiolformate Other physical properties: density 1.201 at 23.8 C., re formed. fractive index 1.4642 at 26.5 C. It was a colorless The inorganic fluoride which serves as the source of 55 liquid which exhibited lachrymatory effects. fluorine can be the fluoride of any of those elements in Analysis.-Theory: C, 60.1%; H, 3.57%; F, 13.6%. groups I to VIII inclusive of the periodic table which Found: C, 61.03%; H, 4.2%; F, 13.6%. have atomic numbers 1 or from 11 to 83 inclusive. F19 Nuclear Magnetic Resonance displayed a lone The ratio of arylchloroformate or arylchlorothiol singlet at --16.5 p.p.m. (CFCI as internal standard). We formate and inorganic fluoride is not critical. How 60 found this absorption characteristic of the fluoroformate ever, it is desirable to use the two reactants in such a grouping. Infrared analysis further supported the ex ratio that there is present in the reaction mixture at least pected structure for phenylfluoroformate, showing strong one atom of fluorine per atom of chlorine. Normally, stretching vibrations for the the reactants are used in such a ratio that there is an excess of inorganic fluoride. 65 The reaction produces a mixture of products. The desired products may be purified in the usual manner. Either solvent extraction or distillation can easily be at about 5.43 u and applied to the work up of the reaction mixture. The reaction between arylchloroformates or aryl 70 chlorothiol formates and the inorganic fluoride to give arylfluoroformates or arylfluorothiolformate should be at about 8.7p. 3,287,388 3 4. EXAMPLE II the process described herein as will be apparent to those Using the same procedure of Example I, 80 g. (0.47 skilled in the chemical arts. It is accordingly intended mole) of phenylchlorothiolformate and 42 g. (1 mol) that the present invention shall only be limited by the of sodium fluoride were mixed in 250 ml of acetonitrile. scope of the appended claim. The mixture was stirred and refluxed for 12 hours. At We claim: the end of this time the mixture was worked up in the A process for producing substituted aromatic com usual manner. A conversion of phenylchlorothiol formate pounds selected from the group consisting of phenyl and of 95% and a yield of phenylfluorothiolformate of 100% naphthy compounds having at least one substituent was observed. selected from the group consisting of fluoroformyl The phenylthiol formate was purified by fractional O (-OCOF) and fluorothiolformyl (-SCOF), compris distillation in vacuo. It had a boiling point of 73° C. at ing contacting at a temperature range of about 20 C. 9 mm. Hg. Other physical properties: density 1.223 at to about 250° C. a substituted phenyl or naphthy com 24 C. and refractive index 1.5273 at 24° C. Infrared pound having bonded directly to an aromatic carbon analysis further confirms the expected structure for atom at least one substituent selected from the group phenylfluorothiolformate. consisting of chloroformyl (-OCOCl) and chlorothiol Analysis.--Theory: C, 53.85%; H, 3.22%; S, 20.51%. formyl (-SCOCl), with an inorganic fluoride selected Found: C, 53.59%; H, 3.39%; F, 20.42%. from the group consisting of sodium fluoride, sodium bi The process of the invention also can be applied to fluoride, potassium fluoride and potassium bifluoride, arylpolychloroformates and polychlorothiolformates. and isolating the resulting fluorine containing compound. While this invention has been illustrated through the use 20 of certain specific inorganic fluorides, it comprises References {Cited by the Examiner broadly the process of preparing arylfluoroformates and UNITED STATES PATENTS arylfluorothioformates by reacting the corresponding 2,438,599 3/1938 Blake. arylchloroformate or arylchlorothiolformate with an in 3,213,062 10/1965 Ellingboe et al. ... 260-463 X organic fluoride of an element having an atomic number 25 3,219,680 1 1/1965 Olah ------260-455 from 11 to 83 inclusive, or, in place thereof, hydrogen fluoride. The reaction can be carried out with or with FOREIGN PATENTS out a solvent. Thus, in addition to the example, there 480,105 2/1938 Great Britain. can be used hydrogen fluoride, potassium fluoride, so OTHER REFERENCES dium fluoride, arsenic trifluoride, ammonium fluoride, ammonium bifluoride, and the like. Some acceptable Ray, Nature (London), 1933, vol. 132, p. 173. solvents, which may be used in combination with the in organic fluorides, are acetonitrile, dimethyl sulfoxide, CHARLESB. PARKER, Prinary Examiner. and the like. DALE R. MAHANAND, DONALD M. PAPUGA, Various changes and modifications may be made in Assistant Examiners.