Patented Dec. 11, 1945 2,390,836 UNITED STATES PATENT OFFICE 2,390,836 METHOD OF ALKYTATING AROMATIC COMPOUNDS George Felix Hennion, South Bend, Ind., and Norbert Francis Toussaint, Louisville, Ky., as signors to E.I. duPont de Nemours & Company, Wilmington, Del, a corporation of Delaware No Drawing. Original application April 30, 1940, Serial No. 332,476. Divided and this applica tion May 19, 1943, Serial No. 487,658 6 Claims. (C. 260-61) This invention relates to a new method of alkyl 0.5 mol of borontrifluoride and 0.5 mol of benzene ating aromatic compounds and more particularly sulphonic acid. A 44.6% yield of mono-dodecyl to a new method for condensing an aromatic com benzene was thus obtained. pound with an aliphatic alcohol containing 3 or The benzene sulphonic acid used in the two more carbon atoms. 5 preceding examples may be generated in situ by It is an object of this invention to develop passing boron trifluoride into a solution of 1 mol a new method of alkylation which gives sat . of benzene and 1 mol of 94% sulphuric acid. This isfactory yields of alkylated products. A further gives complete sulphonation, and the product may object is to provide a novel method of alkylation be used without further purification as a catalyst which makes it unnecessary to use pressure equip 10 in this alkylation reaction. ment or excessive amounts of condensing agent. In accordance with the procedure which is ex LA Still further object is to develop a superior proc emplified by the preceding examples many alkyl eSS for condensing an aliphatic alcohol with an substituted aromatic compounds can be made by aromatic compound. Other objects will appear alkylating an organic compound Containing an hereinafter. 15 aromatic nucleus with an aliphatic alcohol con These objects are accomplished by the follow taining at least three carbon atoms in the pres ing invention according to which an organic com ence of boron trifluoride and an assistant acidic pound containing an aromatic nucleus is alkylated condensing agent selected from the group consist by reacting said organic compound with an ali ing of sulfuric acid and benzenesulfonic acid. phatic alcohol containing at least 3 carbon atoms 20 Mixtures of monoisopropyl benzene and di-iso in the presence of borontrifluoride and an assist propyl benzene can be obtained by thus alkylating ant acidic condensing agent Selected from the benzene with either normal propyl alcohol or is0 group consisting of Sulfuric acid and benzene propyl alcohol. Secondary-butyl benzene and sulfonic acid. The alkylation products thus ob para-di-secondary-butyl benzene may be pre tained can be separated into their constituents by 25 pared by butylating benzene with normal butyl Simple fractionation. alcohol. Alkylation of benzene With either iso The following examples illustrate but do not butyl alcohol or tertiary butyl alcohol yields limit the invention. All parts are given by weight mono-tertiary-butylbenzene and di-tertiary-bu except where it may be otherwise noted. tyl benzene. Reaction of benzene with normal Eacample I.-Amyl ben2eme 30 amyl alcohol in accordance with this invention yields secondary-amyl benzene and di-amylben 25 parts of 94% sulfuric acid was added to a so Zene. Benzene may be alkylated. With a mixture lution of 44 parts (0.5 mol) of n-amyl alcohol in of aliphatic alcohols containing 6 and 7 carbon 312 parts (4 mols) of benzene previously satu atoms obtainable in the methyl alcohol Synthesis rated with 34 parts (0.5 mol) of boron fluoride. 35 to yield mono-, di-, and tetra-alkylated benzenes. After heating for 5A hours the upper layer was Mono-octyl benzene, di-octyl benzene, and tri separated, washed and fractionated. Distillation octylbenzene may be prepared in accordance with gave 59.2 parts (80%) of Sec-amyl-benzene. the present invention by alkylating benzene with Eacample II.-Dodecylbenaene normal octyl alcohol. Alkylation of naphthalene 0.5 mol of n-dodecyl alcohol was heated for 10 40 with octyl alcohol yields a mixture of mono-octyl hours with 2 mols of benzene in the presence of 1. naphthalene and di-octyl naphthalene. A mix mol of 94% sulphuric acid and 0.5 mol dif boron ture of mono-octyl beta-methyl naphthalene and trifluoride. A 46.4% yield of monododecyl ben di-octyl beta-methyl naphthalene can be pre Zene was thus obtained. pared by alkylating beta-methyl naphthalene 45 with normal octyl alcohol. The reaction of 2 Eacample III-Butylbenzene ethyl-hexanol with benzene yields a mixture of A 63% yield of mon-butyl-benzene was ob mono-2-ethyl-hexylbenzene and di-2-ethyl-hexyl tained when 0.5 mol of n-butyl alcohol was heated benzene. When decyl alcohol is used to alkylate for 4 hours with 2 mols of benzene in the presence benzene, a mixture of monodecyl benzene and di of 0.5 mol of borontrifluoride and 0.5 mol of ben 50 decyl benzene is obtained. Similarly, when nor Zene Sulphonic acid. mal decyl alcohol is used to alkylate meta-xylene, a mixture of the decyl and didecyl xylenes is ob Eacample IV.-Dodecyl benaene tained. Decyl tetrahydronaphthalene may be 0.5 mol of n-dodecyl alcohol was heated for 10 made by the reaction of decyl alcohol with tetra hours with 2 mols of benzene in the presence of 55 hydronaphthalene. When benzene is alkylated 2 2,390,836 with normal dodecyl alcohol, mono-dodecyl ben 2. A process for alkylating an organic con zene is obtained along with some di-dodecyl ben pound containing an aromatic nucleus which zene. Reaction of normal dodecyl alcohol with comprises reacting Said compound with an ali naphthalene yields mono-dodecyl naphthalene phatic alcohol containing at least 3 carbon atoms and di-dodecyl naphthalene. Reaction of normal in the presence of borontrifluoride and sulfuric dodecyl alcohol with diphenyl oxide yields mono acid. dodecyl diphenyl oxide. 3. A process for alkylating an aromatic hydro In place of the alcohols which are mentioned carbon of the benzene and naphthalene series above we may use hexyl alcohol, cyclohexanol, which comprises reacting said hydrocarbon with methyl cyclohexanol, nonyl alcohol, etc. 10 an aliphatic alcohol containing at least 3 carbon It is apparent that a wide variety of aromatic atoms in the presence of boron trifluoride and an compounds can be alkylated by the methods dis assistant acidic condensing agent Selected from closed above. In accordance with this invention the group consisting of sulfuric acid and benzene sulfonic acid. it is possible to alkylate still other aromatic 4. A process for alkylating an aromatic hydro compounds such as cymene, anthracene, phe 5 carbon of the benzene and naphthalene series nanthrene, fluorene, methyl benzoate, dimethyl which comprises reacting said hydrocarbon with andline, acetophenone, carbazole, thianthrene, an aliphatic alcohol containing at least 3 carbon phenol, cresol, naphthol, anisole, phenetole, atoms in the presence of borontrifluoride and sul brombenzene, etc. furic acid. This application is a division of our Copending 20 5. A process for alkylating benzene which com application, Serial No. 332,476, filed April 30, 1940. prises reacting benzene with an aliphatic alcohol Resort may be had to such modifications and containing at least 3 carbon atoms in the presence equivalents as fall within the spirit and scope of of boron trifluoride and an assistant acidic con the appended claims. densing agent selected from the group consisting We claim: 25 of Sulfuric acid and benzenesulfonic acid. 1. A process for alkylating an organic com 6. A process for alkylating benzene which com pound containing an aromatic nucleus which prises reacting benzene with an aliphatic alcohol comprises reacting said compound with an ali containing at least 3 carbon atoms in the presence w phatic alcohol containing at least 3 carbon atoms in the presence of boron trifluoride and an assist 30 of borontrifluoride and Sulfuric acid. ant acidic Condensing agent Selected from the group consisting of sulfuric acid and benzenesul GEORGE FELIX HENNION. fonic acid. NORBERT FRANCIS TOUSSANT.