Molar concentrations of the dimerized product range from 10 to 75% with the balance being diluent. The pH of the slurry is adjusted (with vigorous stirring) to 9.6 with 1 M sodium hydroxide solution, pausing between additions to assure the pH has stabilized before continuing. The General Procedure for Catalyst Testing described above is used. Sections from each block were deparaffinized and stained with hematoxylin-eosin (H&E), with periodic acid-Schiff (PAS), and with van Gieson’s method. Step 1. A major problem with separation schemes such as described above is that the para isomer of the three possible xylene isomers is present in only about 20% of the equilibrium mixture. The zeolite catalysts were analyzed in the 2θ range of 5° to 70° with scanning rate of 0.02 degrees per second at temperature of 25° C. XRD pattern for zeolite catalysts shown in FIG. It exists in three different isomeric forms named ortho-, meta- and para-xylene. The isomers of xylene were prepared by employing the procedure described in the Example 1. Examples of effective catalysts include sulfonic acid; cation exchange resins [(e.g., those that contain sulfonic acid groups such as Amberlyst 15; Ostion KS (H+ form)]; supported and unsupported metal oxides and mixed metal oxides, including silica-alumina-nickel oxides, titanium dioxide, nickel oxides on alumina, hydrogen-containing boron oxide compounds, bismuth oxides, phosphorous oxides; sodium or lithium metals or compounds supported on a porous potassium salt; t-butanol; zeolites; and sulfuric acid. (2015), Laboratory Investigation To analyze this pattern, the scores were stratified and cross-tabulated for kappa analysis according to the preparation method, tissue type, tissue sample, stain, and individual pathologist and institution. Van Gieson staining methods as used for the xylene-free and conventional sections. It is primarily a synthetic chemical, but it can occur naturally in coal, coal tar, and during forest fires. The source of isobutylene can be any that is convenient, including but not limited to processes such as the cracking of methyl tertiary butyl ether (MTBE), the dehydration of isobutanol, butene skeletal isomerization, and the dehydrogenation of isobutane. It is an object of the present disclosure to provide safe and economic process for the preparation of alkyl aromatic compounds using the basic alkylation catalyst composite. A large but simple waterbath with racks facilitated rapid immersion of the of the xylene-free slides. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. A need thus remains for a process to make xylene that is efficient, avoids costly steps such as isolation and separation, and favors production of the para isomer. In only a few instances did the kappa values rise to moderate agreement; most were in the slight to fair range. Alternatively, the metal(s) can be deposited on a previously pilled, pelleted, beaded, extruded or sieved particulate support material by the impregnation technique. Example 1: Preparation of Ba—X Zeolite Using Na—X Zeolites. Presumably, solutions made up earlier in the week were used. The conventional van Gieson sections were stained on an ordinary working day at the other participating laboratory. A non-oxidative process is provided by not using a feed containing air or oxygen, and by preventing air intrusion into the process through the careful construction and maintenance of tight, well-sealed equipment.