Abstract: Surface-modified organic semiconductors and methods for making surface-modified organic semiconductors are disclosed. More particularly, surface-modified thin films are provided, the surface-modified thin films comprising a first layer comprising a polyaromatic organic semiconductor and a surface layer in direct contact with the first layer, the surface layer comprising an addition reaction product of the polyaromatic organic semiconductor with, for example, a dienophile, wherein the first layer is substantially free of the addition reaction product of the organic semiconductor with the dienophile. Also provided are surface-modified single crystals comprising a core comprising a polyaromatic organic semiconductor and a coating in direct contact with the core, the coating comprising, for example, an addition reaction product of the polyaromatic organic semiconductor with a dienophile, wherein the core is substantially free of the addition reaction product of the organic semiconductor with the dienophile.

Abstract: A method for the synthesis of cyclobuta aromatic compounds by cyclizing two ortho dibromoalkyl substituents is described. Using a mediator, such as nickel metal, and continuous removal of product from contact with the mediator, high product yields are achieved. A method for bromination of ortho alkyl substituents of aromatic compounds is also described.

Abstract: The present invention describes organic solvent-soluble Diels-Alder adducts of polycyclic aromatic compounds, such as, oligothiophene, perylene, benzo[ghi]perylene, coronene and polyacenes, with variety of dienophiles containing at least one heteroatom and in some cases two heteroatoms bonded to aromatic moiety, such as, thioxomalonates, azodicarboxylates, thialdehyde, acylnitroso and N-sulfinylamides. The Diels-Alder adducts are prepared by a simple, one step cycloaddition reaction of the polycyclic aromatic compounds, such as, pentacene, or other fused aromatic compounds, with heterodienophiles. The Diels-Alder adducts according to the present invention all form soluble adducts with pentacene and can be converted back to pentacene by retro-Diels-Alder reaction at moderate (60-250° C.) temperatures both in bulk, in solution or as thin-films.

Abstract: 1,2-dichloroethane is continuously and completely removed and recovered from the off-gas obtained during the production of 1,2-dichloroethane by subjecting ethylene to an oxychlorination reaction with hydrogen chloride and oxygen. The off-gas is initially contacted with active carbon, then incinerated at temperatures higher than 900.degree. C. and ultimately freed from hydrogen chloride and chlorine, and the active carbon is freed from 1,2-dichloroethane and regenerated by treating it with hot steam. More particularly, the off-gas loaded with the 1,2-dichloroethane and having a temperature of 1.degree. C. to 10.degree. C. is heated to a temperature at least 20.degree. C. higher than the respective dew point of water and contacted with the active carbon.

Abstract: Cyclohexane derivatives such as cyclohexanol and cyclohexyl carboxylates are produced directly from aromatic hydrocarbons. The reaction may be carried out, under hydrogenation conditions, by reacting an aromatic hydrocarbon with hydrogen and a reagent selected from the group consisting of water, and carboxylic acids in the presence of a strong acid and a hydrogenation catalyst.