Mixed alkali salts of boric acid and other oxy-acids - having carbonate, phosphate-perchlorate, sulphate and selenate anions, useful as redox catalysts

摘要

New mixed alkali salts (I) of boric acid and other oxyacids have an alkali metal: B molar ratio of 1.01 to 1000 and contain carbonate, phosphate-perchlorate, sulphate and contain carbonate, phosphate-perchlorate, sulphate and selenate anions. They contain (a) small amts. of 4 times O-co-ordinated B and (b) small amts. of O in the 1-oxidn. state. They are (c) paramagnetic and (d) have electron spin resonace spectra with g-values close to 2. They have (e) 2 or more phases, (f) the phase(s) present in excess acting as stabilising matrix for the phase present in small amt., whilst (g) the phase which causes properties (a) to (d) requires a very small wt. fraction. The absorption spectum of (I) pref. has a max. between 700 and 750 nm. (I) can be produced simply be tempering or fusing the components. Matrix imparts almost unlimited stability. Metastable species impart catalytic activity, esp. for redox reactions, e.g. the decomspn. of NOx to N2 and O2, the reaction of NOx and CO to N2 and CO2, the oxidn. of CO to CO2 at 400-500 degrees C, redox reactions of organic substrates, e.g. hydrocarbons, redox reaction in melts, e.g. oxidn. of cyanides with air. (I) are useful for replacing heavy catalysts where these are harmful and can be used in conjunction with inert supports.