United States Patent Office Patented Oct
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3,535,391 United States Patent Office Patented Oct. 20, 1970 1. 2 the benzyl chloride is frequently used in industrial applica 3,535,391 STABILIZING COMPOSTIONS tions in a water free condition, it was necessary for the Glendon D. Kyker, Chattanooga, Tenn., assignor to user to separate the benzyl chloride from the water or Weisicol Chemical Corporation, Chattanooga, Tenn., a alkali solution. For a customer desiring benzyl chloride corporation of Tennessee free of water, anhydrous benzyl chloride has sometimes No Drawing. Continuation-in-part of application Ser. No. been stored and shipped in more expensive containers of 591,445, Nov. 2, 1966. This application Apr. 7, 1969, glass or silver, such materials being devoid of catalytic Ser. No. 814,518 activity. The portion of the term of the patent subsequent to The use of strong acids has also been proposed as Jan. 9, 1985, has been disclaimed O stabilizers for aralkyl halides. However, these acids often Int. CI. C07c 25/00, 25/14 cause corrosion of the containers and tend to deteriorate U.S. C. 260-651 10 Claims the aralkyl halides at high temperatures. In addition to condensation with itself, aralkyl halides ABSTRACT OF THE DISCLOSURE often form condensation products with relatively stable 5 hydrocarbons, particularly in Friedel-Crafts condensa New stabilized aralkyl halide compositions. tions catalyzed by metal contaminates. This reaction is undesirable in the case of aralkyl halides where they are stored or treated in solution with aromatic hydrocarbons. This application is a continuation in part of my copend The aromatic hydrocarbons may be inherently present as a ing application Ser. No. 591,445 filed Nov. 2, 1966 and result of the preparation of the aralkyl halides. For ex now abandoned. ample, in the preparation of benzyl chloride from toluene, This invention relates to the stabilization of aralkyl some of the starting material may be retained in solution halides. More particularly, this invention relates to com in the final product. Other aromatic hydrocarbons which positions and a process for preventing the deterioration may be present and may serve as a co-reactant are ben of aralkyl halides through Friedel-Crafts reactions cata Zene, Xylene, and the like, as well as their halo- and lyzed by metal contamination. alkylhalo-substituted compounds. Aralkyl halides deteriorate in storage and handling Thus, there is a present need for a process of stabiliz due to the effects of various conditions encountered there ing aralkyl halides and for stabilized aralkyl halide com in. The principal cause of instability of the aralkyl halides positions not requiring water, aqueous solutions, strong is contamination with various metals. This contamina 30 ly alkaline materials or strong acids. Such process and tion catalyzes Friedel–Crafts type condensations result compositions would permit aralkyl halides to be shipped ing in lowered purity and in some cases complete resini and stored in metallic containers without harmful de fication. The contamination may be due to the presence of gradation of the halide or damage to the container. the metals themselves, such as iron, nickel, copper, tin, Therefore it is one object of the present invention to aluminum, antimony, boron, cadmium, manganese, 3 5 provide stabilized aralkyl halide compositions. titanium, tungsten and zinc, or to the presence of salts or It is another object of the present invention to pro other compounds of the metals. vide a process for stabilizing aralkyl halides during prep The degree of instability of the aralkyl halides varies aration, purification, storage and use. considerably depending on such factors as the degree Still another object of the present invention is to pro of initial purity, the nature of the container and the 40 vide aralkyl halide compositions which are resistant to conditions under which the aralkyl halide has been proc Friedel-Crafts condensations and polymerization catalyzed essed, purified and stored. This lack of stability is a serious by metal contamination. problem which results in loss of the compounds them These and other objects and advantages of the present selves and frequently damages to the containers and stor invention will be readily apparent from the ensuing de age tanks. Among the halides the chlorides in particular scription and examples. tend to decompose under normally encountered storage The stabilizing aralkyl halide compositions of the pres conditions and are not considered safe for transporting ent invention comprise an aralkyl halide and a compound as industrial chemicals in iron drums. The instability prob of the formula lem of these compounds is distinct from the instability R problem encountered with the alkyl halides such as car bon tetrachloride where the instability is largely brought / about by contamination with moisture. To correct this R3 (I) type of instability, dehydrating agents have been utilized, wherein M is selected from the group consisting of phos especially anhydrous salts which react with the water to phorus, arsenic, PFO, ASRO, form stable hydrates. In contrast the present instability problem exists even in the absence of water. X X Of particular commercial importance is benzyl chlo P. and As ride. Benzyl chloride is normally prepared by the chlori R4 R4 nation of toluene leading to a product having therein X is selected from the group consisting of chlorine, bro a proportion of benzal chloride and benzotrichloride along 60 mine and iodine; R4 is selected from the group consisting with the benzyl chloride. This commercial product tends of chlorine, bromine, iodine and Z; and Z, R1, R and R. to undergo undesirable condensation or decomposition, or are independently selected from the group consisting of both, in storage and it oftentimes develops a dark color. alkyl and haloalkyl containing from one to ten carbon These objectionable reactions may occur not only during the storage and handling but also during the separation and atoms and purification of benzyl chloride or other desired product from the mixture of compounds obtained in the chlorina tion of toluene. Heretofore when benzyl chloride has been shipped in Yin iron drums, an aqueous solution of an alkali such as so 70 wherein n is an integer from 0 to 1, R5 is an alkylene group dium carbonate has been mixed with the benzyl chlo containing from one to ten carbon atoms; Y is selected ride to prevent the above mentioned deterioration. Since from the group consisting of chlorine, bromine and alkyl 3,535,391 3. 4. and haloalkyl containing from one to ten carbon atoms, tion have the formula wherein R' and R'' are independ and n is an integer from 0 to 5. ently selected from the group consisting of hydrogen, chlo The process of the present invention comprises adding rine and bromine, and R is independently selected from to the araykyl halide to be stabilized against Friedel the group consisting of chlorine, bromine, iodine, alkyl Crafts reaction catalyzed by metal contamination, an of up to six carbon atoms and chloroalkyl of up to six effective stabilizing annount of a compound of structural carbon atoms. Formula I. Preferably, an effective amount of the com The aralkyl halides ar exemplified by the group con pound described in the paragraph following structural sisting of Formula I is utilized. benzyl chloride The compounds of Formula I which are useful to stabi 10 2-chlorobenzylchloride lize aralkyl halides in the composition and process of the 4-chlorobenzylchloride present invention are exemplified by: trimethylphosphine, 2,4-dichlorobenzylchloride trimethylphosphine oxide, trimethylphosphine dichloride, 2,5-dichlorobenzylchloride trimethylphosphine dibromide, trimethylphosphine di 2,6-dichlorobenzylchloride iodine, tetramethylphosphonium chloride, trimethylarsine, 2,4,6-trichlorobenzylchloride trimethylarsine oxide, tetramethylarsonium iodide, ethyl 2,3,6-trichlorobenzylchloride dimethylphosphine, diethylmethylarsine, diethylmethyl 3,4,5-trichlorobenzylchloride phosphine, ethyldimethylarsonium iodide, triethylarsine 2,3,4,5-tetrachlorobenzylchloride oxide, triethylphosphine, triethylarsine, triethylphosphine 2,3,4,6-tetrachlorobenzylchloride oxide, butyldimethylphosphine, butyldimethylarsine, butyl 20 2,3,5,6-tetrachlorobenzylchloride dimethylphosphine oxide, trioctylphosphine, trioctylphos pentachlorobenzylchloride phine dichloride, trioctylphosphine oxide, (trifluoro o-methylbenzylchloride methyl) dimethylphosphine, (trifluoromethyl) dimethyl p-methylbenzylchloride arsine, tris(trifluoromethyl) phosphine, tris(trifluoro 2,3-dimethylbenzylchloride methyl) arsine, triphenylphosphine, triphenylarsine, tri 3,4-dihexylbenzylchloride phenylphosphine oxide, triphenylphosphine dichloride, 2,5-dipropylbenzylchloride benzyltriphenylphosphonium chloride, methyltriphenyl 2,4,5-tributylbenzylchloride phosphonium chloride, diphenyltolylphosphine oxide, di 2,4,6-tripentylbenzylchloride phenyltolylarsine, benzyldiphenylphosphine oxide, benzyl 2,3,4,6-tetramethylbenzylchloride diphenylphosphine, dibenzylphenylphosphine, dibenzyl 2,3,5,6-tetraethylbenzylchloride phynylphosphine oxide, phenyldi-p-tolylarsine dichloride, 2,3,4,5-tetramethylbenzylchloride tri-p-tolylarsine, tri-p-tolylphosphine, tri-p-tolylphosphine benzal chloride oxide, (o-chlorophenyl) diphenylarsine, (o-bromophenyl) o-methylbenzalchloride diphenylphosphine, (o-chlorophenyl) diphenylphosphine, p-methylbenzalchloride tris(p-chlorophenyl) phosphine oxide, (p-bromophenyl)- 3. 5 m-methylbenzalchloride phenyl-p-tolylarsine, (dibromomethyl) triphenylphos