GB962954A - Boron compounds - Google Patents

Abstract

Compounds having the general formulae M[B10H9-yXyZ]b . . . (1) and B10H8-yXy.2Z . . . . (2) where M is an atom or group of atoms which forms in aqueous solution a cation of valency of from 1 to 3; X is a group which can be bonded to a nuclear carbon of a carbocyclic aromatic compound by replacement of hydrogen; Z is an organic sulphide, a tertiary phosphine, a tertiary amine, or an amide of a carboxylic acid; "b" is the valancy of M; "y" can be 0-9 for formula (1) and 0-8 for formula (2) are useful sequestering agents for heavy metals including said compounds in which M is H +, and particularly, the alkali metal and alkaline earth metal salts. Thus a mixture of hydrocarbons which contains a copper salt of an organic acid, e.g. copper stearate, is throughly agitated with an aqueous ammoniacal solution of any of the alkali metal or alkaline earth metal salts of formula (1), e.g. CsB10H9.S(CH3)2. The hydrocarbon layer is separated completely free from the copper salt. Similarly, metals, e.g. Cu, Ni, Co, Zn, Cd, Hg, may be removed from aqueous solutions containing them by mixing the solutions with ammoniacal solutions of the acids, and alkali metal, alkaline metal and ammonium salts. The substituted ammonium salts and in general all of the nitrogen base salts as well as the phosphonium and sulphonium salts are also useful in the field of sequestering agents. Specifications 956,391, 956,392, 956,393 and 956,394 are referred to.ALSO:The invention comprises boron hydrogen compounds having the formulae: <TABS:0962954/C1/1> and <TABS:0962954/C1/2> where M is an atom or group of atoms which, in aqueous solution forms a cation, having a valency of from 1 to 3; X is a group which can be bonded to the nuclear carbon of a carbocyclic aromatic compound by replacement of hydrogen; Z is an organic sulphide, a tertiary phosphine a tertiary amine or an amide of a carboxylic acid; "y" can be 0-9 for formula 1 and 0 to 8 for formula (2) and "b" is the valency of M. Of special interest are the "so-called" parent compounds when y=O, i.e. compounds having the formulae: <TABS:0962954/C1/3> and <TABS:0962954/C1/4> where M, "b", and Z have their stated significance. In the compounds (1), (2), (3), and (4) Z may have the formula R2S, R3P, R3N, R2N.CO.H, R2N.CO.CH3, <FORM:0962954/C1/1> wherein the R substituents, which may be the same or different in compounds containing two or more such substituents, are hydrocarbon groups containing up to 18 carbon atoms and wherein two such R groups may be joined to form a ring of which the sulphur, phosphorus or nitrogen atom is a part. Compounds of formulae 3 and 4 may be prepared by treating a compound of the formula: <TABS:0962954/C1/5> wherein M has the meaning previously specified; a1 and b1 are positive whole numbers from 1 to 3 inclusive; and a1 multiplied by the valence of M is 2b1, with an organic sulphoxide, a phosphine oxide or an amine oxide in the presence of a strong acid, (pKa 1.7 or less) e.g. HCl, within a temperature range of -20 DEG C. to 110 DEG C., and isolating the resultant products. Alternatively compounds of formula 3 are prepared by treating decahydrodecaborates of formula 5 with an amide of a carboxylic acid in the presence of a hydrogen halide, and continuing the addition of hydrogen halide until heat is no longer evolved and isolating the product, or on the other hand compounds of formula 4 can be produced by this reaction if heat is then applied, further hydrogen halide added and the resulting product isolated. Compounds of formula (1) and (2) with y=1 or more are prepared in general by a process in which compounds of formulae (3) or (4) as prepared above are treated with a reagent (large numbers of examples in Specification) capable of introducing a monovalent substituent into a benzene nucleus by replacement of hydrogen. Alternatively these compounds may be prepared by treating with a phosphine oxide, a sulphoxide, or an amine oxide an appropriate boron compound which already contains the substituent X, e.g. a compound of formula Ma (B10H10-yXy)b, which compounds are obtained by treating compounds Ma(B10H10)b with the appropriate electrophilic reagent. Compounds in which X is -SR and Z is SR2 may be obtained by treating B10H8.2SR2 with a trisubstituted phosphine or a alkali metal (Ma,K) phthalimide. In all the above reactions, an inert liquid reaction medium may be employed if desired. Processes are also given for producing the above boron compounds with differing R substituents and the X groups introduced may be modified by standard chemical procedures e.g. reduction, esterification, hydrolysis. Variation in the cation M is usually obtained by standard metathetic reactions. The Specification contains 24 examples illustrating various aspects of the invention and contains extensive lists of different types of possible groups M, X and Z and in addition gives the preparation (Examples A and B) of possible starting materials Ma[B10H10]b and [(CH3)4N]2 B10H9C(o)C6H5. Example II discloses that the organic sulphoxide used in the preparation may be prepared in situ by using the appropriate organic sulphide and hydrogen peroxide. Example III illustrates a modification of the process in which (NH4)2B10H10 and R3 instead of R3P->O are used, the product being B10H8. 2P(C4H9)3. The compounds of the invention are useful as combustible components of fireworks; impregnating agents for cellulosic materials to produce resistors (see Division H1), and the acids e.g. formula (1) where M is H+ are useful for etching metals, rust removal, pickling, and scale removal (see Division C7) and are also useful catalysts in the preparation of esters. The acids and their salts particularly alkali and alkaline earth metal salts are useful as sequestering agents for heavy metals both in liquid hydrocarbon and aqueous media. The silver salt may be used in photography (see Division G2). Specifications 956,391, 956,392, 956,393 and 956,394 are referred to.ALSO:Salts of formula M[B10H9-yXyZ]b, in which M is an atom or group of atoms which has a valency of 1 to 3, X is an electrophilic group, able to replace the hydrogen atom on a benzene ring, Z is an organic sulphide, a tertiary phosphine, a tertiary amine or an amide of a carboxylic acid; and y is 0 to 9, can be used to prepare the corresponding acids represented as H B10 H9-y Xy Z. These acids are strong acids, are useful in industrial application where it is desirable to avoid contamination from sulphate, chloride, bromide chloride, phosphate and similar strong acid ions, and thus may be used for etching metals, such as steel, for rust removal, for pickling, for scale removal and similar metal processing operations. For process of producing above salts see Division C2. Specifications 956,391, 956,392, 956,393 and 956,394 are referred to.