Potassium borofluoride

Available forms Crystalline powder, dry amorphous powder, colloidal suspension of dry amorphous powder in oil in boron trifluoride-calcium fluoride, in potassium borofluoride, in boron trifluoride ethyl etherate, in boric acid. 

Synonyms Avogadrite Borate(l-), tetrafluoro-, potassium Potassium borofluoride Potassium fluoroborate Potassium tetrafluoroborate Tetrafluoroborate (1-) potassium... 

Dissolve 34 g. of o-nitroaniline in a warm mixture of 63 ml. of concentrated hydrochloric acid and 63 ml. of water contained in a 600 ml. beaker. Place the beaker in an ice - salt bath, and cool to 0-5° whilst stirring mechanically the o-nitroaniline hydrochloride will separate in a finely-divided crystalline form. Add a cold solution of 18 g. of sodium nitrite in 40 ml. of water slowly and with stirring to an end point with potassium iodide - starch paper do not allow the temperature to rise above 5-7 . Introduce, whilst stirring vigorously, a solution of 40 g. of sodium borofluoride in 80 ml. of water. Stir for a further 10 minutes, and filter the solid diazonium fluoborate with suction on a sintered glass funnel. Wash it immediately once with 25 ml. of cold 5 per cent, sodium borofluoride solution, then twice with 15 ml. portions of rectified (or methylated) spirit and several times with ether in each washing stir... 

The procedure described for the preparation of l-(m-nitro-phenyl)-3,3-dimethyltriazene is the method of Elks and Hey,2 and the preparation of m-nitrobiphenyl is also a modification of their procedure. The other principal methods for the preparation of m-nitrobiphenyl are the decomposition of N-nitroso-w-nitroacetanilide in benzene 3 and the decomposition of alkaline m-nitrobenzenediazohydroxide in benzene.4 Other methods that have been reported include the decomposition of potassium ire-nitrobenzenediazotate in benzene with acetyl chloride,6 the decomposition of m-nitrobenzoyl peroxide in boiling benzene,6 the decomposition of benzenediazonium borofluoride in nitrobenzene 7 at 70°, and the reduction of 4-(3 -nitrophenyl)-benzenediazonium acid sulfate in boiling ethanol.8... 

A species believed to be the monomer cation radical of 9-ethylcarbazole as a green solution in acetonitrile formed by oxidation of 9-ethylcarbazole with iodine-silver(I) perchlorate, was detected by ESR spectroscopy, although the perchlorate of the cation radical could not be isolated subsequent treatment with potassium iodide gave 9,9 -diethyl-3,3 -bicarbazole. The borofluoride salts generated as crystalline materials by oxidation of carbazole or 9-methylcarbazole with tropylium borofluoride in acetonitrile followed by precipitation with methanol are not salts of the monomer cation-radicaP as originally believed. Russian workers have suggested that nitration of carbazole proceeds via a cation radical. ... 

Potassium fluoride, KF.—The fluoride is produced by the interaction of hydrofluoric acid and potassium carbonate or hydroxide by heating potassium silicofluoride or borofluoride with lime and by the action of potassium on fluorine, hydrofluoric add, or silicon fluoride or boride. 

From boracic acid, boron is with difficulty obtained by the action of potassium, aided by heat, which removes the oxygen. Or it may be prepared by the action of potassium on borofluoride of potassium, when boron is separated. KF, BF3-f-K3=4 KF +B. The fluoride of potassium which is formed, is dissolved away by water, and the boron remains as a dark olive-coloured powder. Boron is fixed in the fire, but if heated in oxygen gas it bums brilliantly, being converted,into boracic acid. 

Boron trichloride is prepared by chlorinating a mixture of finely divided carbon and boric oxide at 1600°F to 1800°F (871°C to 982°C). It can also be prepared by heating boric oxide with sodium, potassium, or lithium chloride at 1472°F to 1832°F (800°C to lOOOX) or by heating sodium borofluoride with magnesium chloride at 932°F to 1832°F (500 C to 1000°C) [9]. 

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