Class of Friedel-Crafts Catalysts

The field of this invention relates to novel Friedel-Crafts Catalysts and to processes for the aralkylation of aromatics to produce polybenzyls, manufacture of aromatic ketones, aromatic sulfones and aromatic esters.

This invention relates to novel Friedel-Crafts Catalysts comprising molybdenum compounds. These catalysts are adapted for use in the Friedel-Crafts reactions for the aralkylation of aromatics to produce polybenzyls, the manufacture of aromatic ketones, aromatic sulfones and aromatic esters. These novel Friedel-Crafts Catalysts are molybdenum compounds, particularly molybdenum sulfide, molybdenum silicide, molybdenum selenide and molybdenum telluride.

It is an object of this invention to provide molybdenum containing compounds as catalysts for Friedel-Crafts reactions. It is a further object of this invention to provide molybdenum sulfide, molybdenum silicide, molybdenum selenide and molybdenum telluride as catalysts for the aralkylation of aromatics to produce polybenzyls, the manufacture of aromatic sulfones, aromatic ketones and aromatic esters. Further objects and advantages will become apparent as the description of my invention proceeds.

the aralkylation of aromatic hydrocarbons to produce polybenzyls and the manufacture of ketones, sulfones and esters using various Friedel-Crafts Catalysts has been known to the prior art. For some of these reactions Grosse and Ipatieff in J. Org. Chem. 1, 559 (1936) showed the following order of reactivity of Friedel-Crafts type catalysts: AlCl.sub.3 >ZrCl.sub.4 >TaCl.sub.5 >BF.sub.3 >CbCl.sub.5 >TiCl.sub.4. R. E. Bunk in Twelfth Catalysis Report, John Wiley and Sons, New York, p. 266 (1940) has disclosed a generalized table of reactivity, as follows: AlBr.sub.3 >AlCl.sub.3 >FeCl.sub.3 >ZrCl.sub.4 >TaCl.sub.5 >BF.sub.3 >CCl.sub.4 >TiCl.sub.3 >WCl.sub.6 >CbCl.sub.5 >ZnCl.sub.2 >SnCl.sub.4 >TiCl.sub.4 >BeCl.sub.2 >SbCl.sub.5 >HgCl.sub.2 >CuCl.sub.2 >BiCl.sub.3 >AsF.sub.3.

The Friedel-Crafts Catalysts of the prior art have not been attractive in many instances due to the uncontrollable side reactions. The prior art Friedel-Crafts Catalysts also degrade under reaction conditions and during work-up, and are not recoverable. I have found that by employing molybdenum compounds such as molybdenum sulfide, molybdenum silicide, molybdenum selenide, molybdenum telluride, molybdenum boride and molybdenum carbide the disadvantages of the prior art Friedel-Crafts Catalysts are overcome.

I have discovered that the following molybdenum compounds MoS.sub.2, MoSi.sub.2, MoTe.sub.2, and MoSe.sub.2, MB and Mo.sub.2 C are useful as catalysts for Friedel-Crafts reactions. This discovery is surprising and totally unexpected in regard to the prior art teachings, as the molybdenum compounds have been considered inert chemically. In fact, MoS.sub.2 has been used widely as a lubricant because of its chemical unreactivity and related physical properties.

In comparison with the usual Friedel-Crafts Catalysts listed above the molybdenum compounds of my invention are not consumed in the reactor and may be recovered from the reaction medium unchanged, therefore avoiding expensive and troublesome workup. My catalysts are also inexpensive, stable at elevated temperatures, cause no pollution and are environmentally inert.

My catalysts are particularly suitable for use in the aralkylation of aromatics to produce polybenzyls, for the manufacture of aromatic ketones from aroyl halides and aromatics, for the manufacture of aromatic sulfones from aryl sulfonyl halides and aromatics and for the manufacture of aromatic esters from aroyl halides and phenol and for the benzylation of polystyrene.

The aralkylation of aromatic hydrocarbons is carried out by contacting aromatic halides in the presence of the novel molybdenum-containing catalysts at a temperature and pressure effective for promoting the aralkylation under the catalytic influence of the aforementioned molybdenum compounds. The aralkylation usually is conducted at a temperature of about 60.degree. to 250.degree. C. and the catalyst concentration is in the range of about 0.01 to about 15% by weight of reactants. The novel aralkylation process is suitable for the production of polybenzyls from benzyl halides and halogenated xylenes. In like manner, using applicant's novel catalyst ketones are produced from aroyl halides and aromatics and sulfones are produced from aryl sulfonyl halides and aromatics. Similarly esters are formed from aroyl hallides and phenols. In all these reactions, the reaction temperature is kept in the range of about 60.degree. to 250.degree. C. and if more than one reactant is present the mole ratio of the reactants is about 1:1 to 3:1. The molybdenum catalyst is usually employed at a concentration of about 0.01 to 15% by weight of the reactant. In some instances the reaction is conducted in the presence of inert hydrocarbon solvents such as benzene or xylene. The polybenzyls produced by the novel aralkylation process are useful as laminants and glass reinforced laminants. The ketones, particularly methylated benzophenones are useful as herbicides. The methylated diphenylsulfones and the related aroyl sulfones are used as stabilizers for polyesters.

The following examples illustrate the preferred embodiment of this invention. It will be understood that these examples are for illustrative purposes only and do not purport to be wholly definitive with respect to conditions or scope of the invention.

A mixture of 34.5 ml (0.3 mole) of benzyl chloride and 4.8 g (30 mmole) of molybdenum disulfide, MoS.sub.2, was heated at 75.degree.-80.degree. C. for 96 hours. Hydrogen chloride evolved steadily, diminishing in intensity after 48 hours and ceasing by 96 hours. Benzene, 100 ml, was added and the mixture was stirred and refluxed 2 hours, then filtered. The weight of recovered molybdenum disulfide was 4.8 g.

The benzene solution of the polybenzyl was viscous and highly fluorescent. It had adhesive properties. It was evaporated to recover 27 g (100 mole % yield) of hard, solid polybenzyl.

Analysis: Calcd. for (C.sub.7 H.sub.6).sub.n ; C, 93.3%; H, 6.7% Fd.: C, 92.9%; H, 6.7%; Cl, 0.1%. Intrinsic viscosity, 2% in toluene, 0.05.

A mixture of 3.02 g (20 mmoles) of molybdenum disilicide, MoSi.sub.2, and 23.3 ml (0.2 mole) of benzyl chloride was stirred and heated. At 80.degree. C. hydrogen chloride evolved in copious amount and the temperature of the mixture rose to 106.degree. C. in 5 minutes. The mixture became viscous, then solidified. It was kept at 83.degree. C. for 16 hours, dissolved in 100 ml of hot benzene, filtered, and evaporated to give 18.0 (100 mole % yield) of solid polybenzyl that analyzed 92.9% C, 6.3% H, Cl<0.1%. The intrinsic viscosity (IV), 2% in toluene, was 0.07. The recovered MoSi.sub.2 weighed 3.02 g.

A solution of 28.2 ml (0.2 mole) of vinylbenzyl chloride (Dow Experimental monomer XD-1915, 60% m- and 40% p-vinylbenzyl chloride containing 50 ppm of tertbutylcatechol and 1000 ppm of nitromethane) in 100 ml of benzene was refluxed 24 hours to give a viscous solution of polymer. A mixture of 25.6 ml of solution, containing 40 mmoles calculated as monomeric vinylbenzyl chloride, and 0.035 g (0.1 mmole) of molybdenum detelluride, MoTe.sub.2, was stirred and heated to remove benzene, then at 120.degree. C. for 1 hour. HCl evolved. Commercial xylene, 50 ml, was added; the mixture was stirred and refluxed for 2 hours, at which time no more HCl evolved. The xylene solution was poured into 300 ml of methanol to precipitate 4.7 g of white polymer that analyzed C, 89.8%; H, 8.4%; Cl, 0.6%. IV, 2% in o-dichlorobenzene, 0.29.

A mixture of 28.56 ml (0.2 mole) of benzyl chloroformate, ##STR1## and 1 g (3 mole %) of MoS.sub.2 was stirred and warmed. At 52.degree. C. gas evolved at an increasing rate and the temperature rose to 125.degree. C. When the spontaneous heat had subsided, the mixture was kept at 90.degree. C. for 1 hour, treated with 100 ml of toluene, filtered from MoS.sub.2 (1 g recovered) and evaporated to give 22 g of light-brown, clear, hard polymer that analyzed C, 89.9%; H, 6.3%; Cl, 0.2%; IV, 2% in o-dichlorobenzene, 0.06.

A mixture of 23 ml (0.2 mole) of benzyl chloride and 11.5 ml (0.1 mole) of freshly distilled styrene was heated at 60.degree. C. for 15 hours. To the viscous solution was added 0.351 g (1 mmole) of MoTe.sub.2. The stirred mixture was heated at 140.degree. C. for 3 hours, HCl evolving in great quantities; 50 ml of commercial xylene were added, stirring and refluxing continued for 4 hours. The hot solution was filtered into 300 ml of methanol, precipitating 13 g of brown solid polymer that analyzed 92.9% C; 6.8% H; and 0.22% Cl.

A mixture of 23 ml (0.2 mole) of benzyl chloride and 23 ml (0.2 mole) of freshly-distilled styrene was treated as in Example 5 to give 20.5 g of rubbery copolymer that analyzed 92.3% C, 7.6% H, and 0.1% Cl.

A mixture of 23 ml (0.2 mole) of benzyl chloride and 34.5 ml (0.3 mole) of styrene was treated as in Example 5 to give 32.3 g of rubbery copolymer that analyzed 92.8% C, 7.2% H, and 0.04% Cl.

A mixture of 16 ml (0.139 mole) of styrene and 7.05 ml (0.05 mole) of vinylbenzyl chloride was treated as in Example 5 to give 7.7 g of white, solid polymer that analyzed 83.6% C, 6.8% H, and 8.2% Cl.

A mixture of 10.4 g of crystal polystyrene, IR3CO 8A-PED-648, 0.1 mole calculated as styrene, 11.5 ml (0.1 mole) of benzyl chloride, 30 ml of 1,2,4-trichlorobenzene, and 0.2 g of MoTe.sub.2 was stirred at 75.degree. C. for 2.5 hours, HCl evolving rapidly. Benzene (100 ml) was added, the solution filtered from MoTe.sub.2 and a little gelled polymer, and poured into 200 ml of isopropanol. The precipitated polymer was redissolved in benzene and reprecipitated by isopropanol to give 16.8 g of white benzylated polystyrene that analyzed 92.8% C and 6.6% H.

Original polystyrene, 0.7.

Benzylated polystyrene, 1.09

A mixture of 9.4 g (0.1 mole) of phenol, 11.51 ml (0.1 mole) of benzyl chloride, and 0.176 g (0.5 mmole) of MoTe.sub.2 was kept at 55.degree.-65.degree. C. for 24 hours, at which time HCl evolution had stopped. The mixture was diluted with 100 ml of benzene, filtered from MoTe.sub.2, and evaporated to give 18.4 g of cream-colored solid, all soluble in aqueous base, that contained 4- and 2-benzylphenols in the ratio of 1.4:1.

A mixture of 9.4 g (0.1 mole) of phenol, 11.6 g (0.1 mole) of benzoyl chloride and 0.176 g (0.5 mmole) of MoTe.sub.2 was warmed at 30.degree. C. There was a vigorous evolution of HCl. After 1 hour the entire mixture had solidified. It was heated at 60.degree. C. for 2 hours, the solid was broken up, washed with water, dissolved in acetone, filtered from MoTe.sub.2, and evaporated to give 17.6 g (89 mole %) of white crystalline phenyl benzoate, Mp and mixed mp 70.degree. C.

A mixture of 15.46 g (0.1 mole) of m-toluoyl chloride, 24.6 ml (0.2 mole) of p-xylene, and 2 g of MoS.sub.2 was stirred and refluxed. After 24 hours no more HCl evolved. The mixture was diluted with 100 ml of benzene, filtered from 2 g of MoS.sub.2, and distilled to obtain 12.5 g boiling at 245.degree.-250.degree. C./200 of 2,4,3'-trimethylbenzophenone, 82.6 mole % yield.

A mixture of 24.6 mo (0.2 mole) of p-xylene, 19.0 g (0.1 mole) of p-toluene sulfonylchloride, and 0.2 g of MoTe.sub.2 was stirred and heated at 146.degree. C. After 24 hours no more HCl evolved. The cooled mixture was diluted with 100 ml of benzene, filtered from MoTe.sub.2, and evaporated to obtain 26.6 g (100 mole %) of 2,5,4'-trimethyl diphenyl sulfone, mp 108.degree.-109.degree. C. from isopropanol. H. Drews, S. Meyerson, and E. K. Fields, J. Am. Chem. Soc., 83, 3871 (1969) gave the mp as 108.degree.-110.degree. C.