Abstract: 4-Fluorobenzaldehyde is produced by a commercially feasible process. The process comprises heating a mixture of fluorobenzene and a strong Lewis acid with dissolved hydrogen halide in an atmosphere of carbon monoxide at about 45 to about 100° C. and at a total pressure of about 150 psig up to the maximum pressure rating of the reactor. Formed is a reaction mass containing a Lewis acid complex of 4-fluorobenzaldehyde and at least a halobis(fluorophenyl)methane by-product. The complex is broken by quenching the reaction mass with a Lewis acid-solvating liquid to liberate 4-fluorobenzaldehyde. By-product halobis(fluorophenyl)methane is converted to di(fluorophenyl)methanol to avoid potential corrosion problems and formation of light sensitive color bodies in the recovered 4-fluorobenzaldehyde.

Abstract: The yield of acetyl chloride from the reaction between acetic anhydride and hydrogen chloride is increased by withdrawing acetyl chloride, optionally together with at least some of the acetic acid by-product, from the reaction mixture as the reaction proceeds and recycling the remainder of the reaction mixture to the reactor for reaction with additional hydrogen chloride.

Abstract: This invention relates to an improvement in a process for preparing a product predominant in decabromodiphenylethane. In the improved process the diphenylethane is reacted with bromine in the presence of bromination catalyst in a reaction vessel by feeding diphenylethane to the reaction vessel below the liquid level of bromine in the reaction vessel. The improvement comprises contacting diphenylethane, bromine, and catalyst at a rate sufficient to obtain a diphenylethane predominant product having enhanced color and particle size.