摘要:
The invention relates to the use of tripotassium citrate monohydrate and other alkali metal salts of polybasic acid as bench life extenders in heat curable hot box foundry mixtures comprising sand, thermosetting binder resin, and a latent acid catalyst composition. In one embodiment, the thermosetting binder resin is a phenolic resole resin modified with urea formaldehyde resin. In another embodiment, the thermosetting binder resin is a furfuryl alcohol resin modified with urea formaldehyde resin.
摘要:
A large group of derivatives of 3-furoic acid and 3-furyl ketones can be prepared in high yield by a process which consists of reacting an .alpha.,.beta.-unsaturated ketone having either an .alpha.-carboalkoxy or .alpha.-acyl group with N-bromosuccinimide and thermally cyclizing the resulting bromine containing intermediate.