Synthesis of 1, 2, 3-Trimethylbenzene, 1-Ethyl-3-Methylbenzene, and m-Xylene by Dehydrogenation of Corresponding Cyclohexene Intermediates

Abstract

Tu' CONJUNCTION with Methods of synthesis for l-ethyl-3-methylbenzene,of m-xylene the intermediate 1,2,3-trimethylbeiizene, and m-xylene which are applic-3,5-dimethyll-1 -cyclohexanol was prepared b y hydrogenratory to study aromatic able to the production of 10-gallon quantities of pure hyhydrocarbons as possible drocarbon are described. The three compounds were preation of commercial 3,5-dicomponents of aviation g a m pared by the dehydrogenation of suitablecyclohexeneintermethy 1 -1 -hydroxybenzene line, the development of mediates. Physical constants and freezing or melting (3,5-x~lenol, 3,5-dimethylmethods of synthesis readily curves for the three aromatic hydrocarbons are reported.Phenol). adaptable to the preparation In the large scale prepaof 10-gallon quantities of the ration of these compounds pure hydrocarbons was necessary. This paper presents the methseveral runs were made at each stage before the next step was ods developed for the large scale syntheses of 1,2,3-trimethylbegun. For this reason typical quantities of reactants used are benzene (6), 1-ethyl-3-methylbenzene (,$?), and mxylene by the given under experimental details for the stepwise synthesis of dehydrogenation of the corresponding cyclohexene interthe hydrocarbons. mediates.Physical constants of the 1,2,3-trimethylbenzene, l-ethyl-3-1,2,3-Trimethylbenzene was prepared according to a general methylbenzene, and m-xylene are listed in Table I together with method outlined by Tom and Boord (9) in which piperylene selected literature values. The properties were obtained by (l,3-pentadiene) and crotonaldehyde were condensed to the methods previously described ( 3 ) . Freezing curves for 1,2,3-2,6-and 5,6-dimethyl-3-cyclohexene-l-carboxaldehydes, followed trimethylbenzene and mxylene, and a melting curve for 1-by hydrogenation to the 2,3-and 2,6-dimethylcyclohexylcarbinols, dehydration to the 1,2,3-trimethylcyclohexenes, and a program at this labo-

Synthesis of the Three Trimethyl- And Certain Other Polyalkyl-Benzenes

“…Uncorrected distillation temperatures. 1 Determined in a simplified freezing point apparatus (14, 15) using a copper-constantan thermocouple. 6 Computed from observed freezing points and published data (16,17). "…”

In Situ Generation of Ammonia: an Efficient Catalyst for the Synthesis of Phenol-Aniline-Formaldehyde Resol Resin

“…Titrimetric methods are widely used for the determination of free formaldehyde concentration, because of simplicity and accuracy. Reynolds and Irwin reviewed the different titrimetric methods available for measuring small quantities of formaldehyde and concluded that sodium sulphite method is a simple and adaptable method for the determination of formaldehyde [21]. When formaldehyde reacts with sodium sulphite, it forms formaldehyde bisulphite as an addition product and sodium hydroxide is liberated.…”

Pyrolytic and Catalytic Decomposition of Hydrocarbons

“…The dehydrogenation of the isomers of 1,2,3-trimethylcyclohexene, l-ethyl-3-methylcyclohexene, and 2,4-dimethyl-1-cyclohexene was studied by Reynolds, Ebersole, Lamberti, Ohanan, and Ordin (88). The authors employed a commercial chromiaalumina catalyst at 450°to 470°C.…”

“…A new process development, Thermofor pyrolytic cracking (TPC) has been announced (88) for the high temperature, low pressure thermal decomposition of stocks ranging from ethane to reduced crudes for the production of ethylene and aromatics. Based on the technique employed in the Thermofor catalytic cracking (TCC) process, the hydrocarbon feed is brought into continuous contact with a moving bed of preheated inert solid particles which flow by gravity downward from an elevated heater into a reactor directly below where the decomposition occurs.…”