United States Patent (19) 11, 3,974,229 Van Sorge (45) Aug. 10, 1976 (54) PREPARATION OF ORTHO-ALKYLATED Primary Examiner-Norman Morgenstern PHENOLS Attorney, Agent, or Firm-William F. Mufatti; Edward 75 Inventor: Bernardus J. Van Sorge, Selkirk, A. Hedman 73) Assignee: General Electric Company, Pittsfield, Mass. 57 ABSTRACT 22 Filed: Feb. 11, 1971 There are provided alkylation catalysts comprising (21) Appl. No.: 114,698 magnesium oxide mixed with and bonded by manga nese oxides. These are used in processes for the vapor Related U.S. Application Data phase ortho-alkylation of phenols with an alcohol. The 63 Continuation-in-part of Ser. No. 846,973, Aug. 1, present catalysts are advantageous in that they provide 1969, abandoned, which is a continuation-in-part of a substantially increased total useful life, a reduced in Ser. No. 717,919, April 1, 1968, abandoned. duction period for maximum reaction selectivity, elim ination of catalyst losses in comparison with the pow 52 U.S. Cl............................. 260/621 R; 252/471; ders or weakly sintered composites of the prior art and 260/620; 260/624 C increased selectivity for ortho-substitution. Treatment (5) Int. Cl’.......................................... C07C37/16 of the new catalysts with methanol vapor before use 58 Field of Search............. 260/621 R, 624 C, 620 enhances their activity in converting phenols to 2,6- 56 References Cited Xylenol and results in a significant increase in produc UNITED STATES PATENTS tion rate. 3,446,856 5/1969 Hamilton.................... 260/621 R X 15 Claims, No Drawings FOREIGN PATENTS OR APPLICATIONS 717,588 10/1954 United Kingdom............. 260/621 R 3,974,229 1 2 nating the pulverized magnesium oxide with an aque PREPARATION OF ORTHO-ALKYLATED ous solution of manganese sulfate. Preferably, the man PHENOLS ganese sulfate constitutes from 2 to 10% of the catalyst on a dry solids basis. After mixing, it is preferred to CROSS-REFERENCE TO RELATED mold the catalyst to a desired shape. It is disclosed that APPLICATIONS interaction between the manganese salt and the magne This application is a continuation-in-part of copend sium oxide upon contact with water from wet mixing or ing U.S. patent application Ser. No. 846,973, filed Aug. impregnation with aqueous solution is accompanied by l, 1969, which in turn is a continuation-in-part of Ser. the evolution of heat. Since the surface to weight ratio No. 717,919, filed April 1, 1968 both now abandoned. 0 of the magnesium oxide is very high, for example, of This invention relates to the ortho-alkylation of phe the order of 180 square meters per gram, the heat nols and more particularly, to the vapor phase ortho brings about a noticeable increase in the mixture tem alkylation of phenols by reaction of a non-ortho perature under normal impregnating or mixing condi alkylated phenol with an alcohol in the presence of a tions. This appears to result in the formation of a lattice catalyst comprising magnesium oxide mixed with a 5 of enhanced catalytic activity containing the magne manganese oxide. sium oxide and manganese sulfate. With the catalyst of application Ser. No. 717,919, BACKGROUND OF THE INVENTION selectivity favoring ortho-methylation over meta- or In commonly assigned Hamilton U.S. patent applica para-methylation is the same as that of the Hamilton tion Ser. No. 371,189, filed May 29, 1964, now U.S. 20 patent at temperatures as low as 440C. It is advanta Pat. No. 3,446,856, there is disclosed and claimed a geous to operate at temperatures as low as 440°C. in method for methylating the ortho positions of phenol stead of, for example, 530°C., because catalyst life is by the vapor phase reaction of a phenol with methanol extended considerably before regeneration or other in the presence of magnesium oxide as a catalyst at a treatment is needed. Such catalysts have been operated catalyst bed temperature in the range of 475 to 600°C. 25 without reduction in catalytic activity for periods in Under the conditions described in the Hamilton patent, excess of 800 hours, in contrast to a maximum life of phenol is selectively ortho-methylated in yields of 95%. 90-100 hours for the Hamilton catalysts. In addition, Thus, the reaction offers a means for economically the magnesium oxide-manganese sulfate catalyst is converting phenol to ortho-cresol, a useful disinfectant superior because of the increased strength imparted to and wood preservative and for converting both phenol 30 the catalyst particles by the manganese oxide lattice and ortho-cresol to 2,6-Xylenol, a monomer which can formed by the reaction between manganese sulfate and be polymerized to form poly(2,6-dimethyl-1,4- magnesium oxide in the presence of water. Therefore, phenylene)oxide, a high performance thermoplastic there is much less tendency for particles of catalyst to material. flake off in operation or from handling and the service While the Hamilton patent provides an economic 35 life is thus extended with a minimum loss of catalyst. synthesis for both 2,6-xylenol and ortho-cresol from Although the catalyst of the said copending applica phenol, the service life of the magnesium oxide catalyst tion Ser. No. 717,919 provides the advantages noted is relatively short due to the high temperature at which above, there is observed an undesirable increase in the the reaction is required to take place, i.e., about 90 to induction period required for maximum reaction selec 100 hours service life at the typical reaction tempera 40 tivity. This means that about 24-100 hours is required ture of about 530°C. Also, the magnesium oxide cata to reach a molar phenol selectivity level of over 90%. lyst of the Hamilton patent is only moderately selective During the induction period, a relatively large amount with respect to methanol, with methanol selectivity of undesired 2,4,6-mesitol is produced. It is believed being in the range of about 40 to 50%. This means that the presence of the sulfate ion in the catalyst is more than about two moles of methanol are 'required 45 responsible for the longer induction period. for each mole of methanol entering into the reaction It has now been found that magnesium oxide mixed with phenol. In addition, the use of unmodified magne or bonded with manganese oxide or a mixture of man sium oxide in powdered form or in the form of a weakly ganese oxides has the advantages of the catalyst of the sintered composite results in a rather large induction above-noted copending application and also, because period for maximum selectivity. The term "induction 50 sulfate is eliminated, has the further advantage of hav period" may be defined as the period from the time of ing a reduced induction period for maximum ortho starting the reaction to the time at which the catalyst alkylation selectivity. Thus, the present invention con reaches and maintains maximum ortho-alkylation se templates an ortho-alkylation catalyst consisting of lectivity. Finally, the use of magnesium oxide in pow magnesium oxide mixed with manganese oxides, sub dered or sintered form provides various processing 55 stantially free of sulfate, permitting the ortho-alkyla difficulties. tion reaction to proceed with a high degree of both Many of the above-noted difficulties are overcome methanol and phenol selectivity and with a reduced by the process of the said copending U.S. patent appli induction period for maximum selectivity. Moreover, cation Ser. No. 717,919, filed Apr. 1, 1968. Therein, a the new catalysts may be molded to any desired shape process is disclosed for the ortho-alkylation of phenol 60 and will have strength properties sufficient to prevent comprising the reaction of a phenol having at least one particles of the the catalyst from breaking or flaking off unsubstituted ortho position with an alcohol in the in operation or handling, thus substantially extending presence of a catalyst consisting of a mixture of magne the service life of the catalyst with a minimum of loss sium oxide and manganese sulfate. during operation. In addition the optimum reaction The catalyst of copending patent application Ser. No. 65 temperature, may be reduced from 500°-540°C. for 717,919 is prepared by pulverizing the magnesium conventional catalysts down to 465-485°C., thereby oxide and wet-mixing the magnesium oxide with man improving the overal economy of the process and in ganese sulfate and water or, alternatively, by impreg creasing the catalyst life further. 3,974,229 3 4 it has also been discovered that if the catalysts ac an alkali such as potassium hydroxide. However cording to this invention are treated with methanol formed, best results are obtained if the manganese vapor before use, there is an unexpected, significant oxides powders are washed with distilled or slightly increase in conversion of phenols to ortho-alkylated alkaline water until substantially free of ions, especially products. This in-situ activation provides an economi sulfate and potassium ions. cal means of heating up a large commercial size reactor In a preferred feature, the catalyst prepared as de and results in a significant increase in production rate, scribed above is activated by exposing it to methanol of at least about 50% and more. vapor, e.g., by heating at a temperature of at least Accordingly, a primary object of the present inven about 250°C., until activation is substantially complete. tion is to provide an improved catalyst for the ortho O In one manner of proceeding, a catalyst according to alkylation of a phenol with an alcohol in a highly selec this invention, e.g., magnesium oxide containing 2 or tive manner and in high yield.