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Typical Rearrangement.-To a constricted tube with a small magnetic stirrer was added 0.26 g (0.001 mol) of 1 followed by 5 ml of dry hexane and 1.3 ml of 1.6 N (0.002 mol) nbutyllithium-hexane. The tube was purged with nitrogen, sealed and placed in a bath at 75 ± 2°with stirring for 48 hr. Water (3 ml) was added to the reaction mixture, and the organic layer was separated and extracted with 3 N HC1. The remaining nonbasic phase was retained for further analysis. The acid extracts were made basic with 50% sodium hydroxide and the basic products extracted with pentane. Careful distillation to concentrate the product resulted in 0.1-0.2 ml of a productspentane solution which was analyzed by gas chromatography.In one run as above, 0.2 ml of TMEDA was added and the reaction time reduced to 1 hr. Controls were also run on solvent plus salt 1 or solvent plus base and analyzed as above.

SynopsisThe polymerization of UV-curable coatings that react by a free-radical mechanism is subject to oxygen inhibition which can be avoided by utilizing an inert atmosphere. We demonstrate that wax barrier coats used to prevent evaporation of volatile reactive monomers are equally effective in preventing oxygen inhibition. No quantitative difference is found between the degree and rate of polymerization in an inert atmosphere or with a wax barrier coating. However, when used above a given ceiling temperature, the wax barrier allows oxygen diffusion which inhibits cure.

A new method for removal of thin films of photoresist polymers has been found. When polymeric films are exposed to ultraviolet light in the presence of air, the material can be removed leaving an extremely clean surface, free of carbonaceous material. This process has been examined for a variety of photoresist polymers as well as on nonphotoresist polymers and on a variety of substrates. The process offers a new method of photoresist removal.

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