Yield: 51.2 g (96%); purity as per HPLC: 99.8%. The amount of base added depends on the number of halogen atoms X2 and X3 to be reacted. 039,465, filed on May 16, 1979, now abandoned. C18 H20 O2 S calculated: C 71.97, H 6.71, S 10.67%. But the particular boron trifluoride complexes required must be prepared in a separate stage. (300.42) found: C 71.7, H 6.7, S 10.5%. The object of the invention was, therefore, to find a novel process of preparation for benzophenone thioethers which avoids the use of aryl alkyl sulfides and also permits the preparation of benzophenone thioethers which carry, in the aliphatic thioether radical, functional groups which would react with AlCl3 under the conditions of the Friedel-Crafts reaction. 2. It has now been found that benzophenone thioethers of the general formula I or Ia ##STR3## in which X is hydrogen, C1 -C4 alkyl, C1 -C4 alkoxy or --COO--(C1 -C4 alkyl) and X1 is hydrogen, Cl, Br or --SR. R is an unbranched or branched alkyl radical having 1-20 C1 atoms, which is unsubstituted or substituted by --OH, --OR1, --O--C4 (O)--R2, --COOR3, --CO-phenyl, --CN, --SR1, --NH2, --NHR4, --NR4 R5 or phenyl, in which R1 is C1 -C4 alkyl, phenyl, C7 -C11 alkylphenyl or phenylalkyl; R2 is C1 -C12 alkyl, C2 -C5 alkenyl or phenyl; R3 is C1 -C12 alkyl and R4 and R5 independently of one another are C1 -C8 alkyl or C2 -C4 hydroxyalkyl, or R4 and R5 together with the N atom to which they are bonded form a pyrrolidine, piperidine, piperazine or morpholine ring, and Ra is an alkylene radical having 2-10 C atoms, which is unsubstituted or substituted by --OH, --OR1 or --O--C(O)--R2 and/or is interrupted by --O--, --NR4 --, --O--C(O)--R6 --C(O)--O--, --C(O)--O--R7 --O--C(O)-- or phenylene, in which R6 is C2 -C8 alkylene, vinylene or phenylene and R7 is C2 -C8 alkylene or 3-oxa-1,5-pentylene, can be prepared by reacting a mono- or di-halogenobenzophenone of the general formula II ##STR4## in which X2 is Cl or Br and X3 is H, Cl or Br, in a polar solvent with a mercapto compound of the formula RSH or Ra (SH)2 in the presence of a base in an amount equivalent to the amount of halogen to be reacted. (350.43) found: C 71.6, H 5.1, S 9.1%. This invention relates to the synthesis of arcmatic compounds of the type which may be produced by a Friedel-Crafts reaction, and is more particularly concerned with a process for producing benzophenone. The mono- and di-halogenobenzophenones of the formula II are known compounds. The novel process is also notable for a short reaction time and a low reaction temperature. Compounds of the formula Ia form from compounds of the formula II in which X3 is hydrogen by reaction with at least 0.5 mol of a dimercaptan of the formula Ra (SH)2 in the presence of 1 mol of base per mol of the compound II. Suitable benzoic acids of the formula II are for example benzoic acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 2-fluorobenzoic acid, 3-fluorobenzoic acid, 4-fluorobenzoic acid, 2-chlorobenzoic acid, 3-chlorobenzoic acid, 4-chlorobenzoic acid, 2-bromobenzoic acid, 3-bromobenzoic acid, 4-bromobenzoic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 2-phenylbenzoic acid, 3-phenylbenzoic acid, 4-phenylbenzoic acid, 4-hydroxybiphenyl-4'-carboxylic acid, 2,4-dimethoxybenzoic acid, 2,6-dimethoxybenzoic acid, 4-carboxydiphenyl ether and 4,4'-dicarboxydiphenyl ether. The product is taken up in ether. This application is a continuation-in-part of copending application Serial Number 480,372, filed March 24, 1943, now abandoned. For example, K. Auwers and L. Beger in Ber. The charge in each case consisted of 468 grams of benzene (6 moles) and 285 grams of benzoyl reaction time for the temperature employed, the .pressure must be such as to ensure the aforesaid practical on-stream reaction time. Obviously, there can be no real upper limit to the pressure range other than one dictated by commercial feasibility. In accordance with the Friedel-Crafts synthesis, when aromatic hydrocarbons and most of their substituted derivatives except the nitro compounds, are contacted with a halogen derivative of an organic compound, in the presence of aluminum chloride or an equivalent metallic halide catalyst and under suitable reaction conditions, the aromatic hydrocarbons and most of their substituted derivatives lose a hydrogen atom from the nucleus while the halogen derivative of an organic compound loses a halogen atom, and the two radicals condense to yield condensation products. All rights reserved. found: C 75.74 H 6.58 S 11.92%. 66 (1933), 411; Chem. REFERENCES CITED The following references are of record in the file of this patent: UNITED STATES PATENTS Name Date Schmerling et al Oct. 2, 1945 OTHER REFERENCES Number Grwcarevic et a1., Berichte, v01. Certain compounds can also be preferentially prepared by the phase transfer process. 4-(2-Hydroxyethyl-mercapto)-4' -isopropyl-benzophenone. of phenyl Grignard added to 1 equiv. The oil residue is distilled in a bulb tube under a high vacuum. The ether layer is washed with water, dried over Na2 SO4 and concentrated. A preferred workup procedure comprises extracting the reaction mixture with water in a liquid-liquid extractor at an elevated temperature under either atmospheric or superatmospheric pressure. The amount of the mercaptan RSH or Ra (SH)2 used must be at least equivalent to the halogen atoms to be reacted, but it can also be considerably higher. Particularly when the process is carried out on a commercial scale, economic considerations make it-preferable to operate in a continuous manner. The benzophenones prepared by means of the process according to the invention, which may be carried out continuously or batchwise, are suitable for use as UV absorbers or as monomers for high temperature resistant polymers. For instance, FR-A-1,375,033 proposes the preparation of benzophenones by reacting boron trifluoride complexes of the reactants in trichloroethylene as diluent. 27.6 g of K2 CO3 are added to a solution of 21.6 g of 4-chlorobenzophenone and 9.9 g of butylmercaptan in 100 ml of dimethylacetamide and the mixture is stirred at 120°-130° C. for 12 hours under nitrogen. Pharm. Benzophenone oxime, polymer-bound, 100-200 mesh, extent of labeling: 1.0-1.5 mmol/g loading, 1 % cross-linked with divinylbenzene PubChem 3 Chemical and Physical Properties No. Thioethers of benzophenone have hitherto in the main been prepared by a Friedel-Crafts reaction with aromatic thioethers. The toluene is distilled off. Ber. 4-(2,3-Dihydroxypropyl-mercapto)-benzophenone. The reaction conditions necessary for effecting the synthesis contemplated herein include temperatures varying between about 300 F. and about 800 F., preferably, temperatures varying between about 400 F. and about 700 F., and reaction times varying between several hours at temperatures approximating the lower limit of the temperature range and about one minute at temperatures approximating the upper limit of the temperature range. Other objects and advantages of the present invention will become apparent to those skilled in the art from the following description. Examples of polar solvents which can be used for the reaction are alcohols, such as methanol, ethanol or isopropanol; glycol ethers, such as butylglycol ether, diethylglycol ether or dimethyldiglycol ether; ketones, such as acetone, methyl ethyl ketone or cyclohexanone; dioxan, dimethylformamide, dimethylacetamide, dimethylsulfoxide, tetramethylenesulfone (sulfolane) or hexamethylphosphoric acid amide. 1. This is uneconomical in the case of valuable reactants and, what is more, requires that in the case of solid reactants the reaction be carried out in a melt, which is technically very complicated. Privacy Policy 2-(2-Hydroxyethyl-mercapto)-4'-methyl-benzophenone. United States Patent 4982005 . To work up the reaction mixture, it may be subjected for example to a steam distillation in order to remove the nitrobenzene, in which case the benzophenone of the formula I generally crystallizes out of the remaining aqueous mother liquor on cooling. (289.39) found: C71.4, H6.2, S 11.1%, 4'-(2-Hydroxyethyl-mercapto)-2,5-dimethyl-benzophenone. © 2004-2020 FreePatentsOnline.com. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT. 220 g of resorcinal and 308 g of 2,4-dihydroxybenzoic acid were suspended in 1 l of nitrobenzene, and 138 g of boron trifluoride were passed in at 24°-40° C. (slightly exothermic reaction). © 2004-2020 FreePatentsOnline.com. & Terms of Use. 87 (1954), 194; Arch. Thioethers of benzophenone have hitherto in the main been prepared by a Friedel-Crafts reaction with aromatic thioethers. embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.