Abstract: The present invention provides a method of production of aromatic hydroxycarboxylic acids by the reaction of alkaline metal salts of phenols or naphthols with carbon dioxide, in which free phenols or free naphthols produced as by-products in the reaction system are removed from the system so as to control the content of free phenols or free naphthols at a suitable level, by which a purer objective compound can be obtained at high yield under the condition of lower temperature and shorter time.

Abstract: A framing code detector includes a shift register supplied with a received framing code and a number of EX-OR gates each having one input connected to a respective stage of the shift register and another input which is supplied with a respective bit of a stored pattern having the inverted form of the anticipated framing code to be received/ a counter is provided for counting the number of times all outputs of EX-OR gates become "1" during a predetermined period, and an identification signal is produced when the count value of the counter is greater than a predetermined value.

Abstract: A process for producing a hydrozybenzonitrile, which comprises reacting a hydroxybenzoic acid ester with ammonia in the vapor phase in the presence of a boron phosphate supported catalyst.