GB1016379A - The preparation of compounds containing a substituted dodecahydrododecaborate anion - Google Patents

Abstract

Polymers containg dodecahydrododecaborate anion may be made by reacting a polymer containing an epoxy group with the acid hydrate H2B12H12nH2O. The polymer may be an addition or condensation polymer and is preferably linear. Polyamides, polyesters and polyureas are preferred condensation polymers. Typical addition polymers have the recurring units <FORM:1016379/C3/1> where M is a cation and a and b are integers whose values are determined by the valence of M, Z and Z1 are hydrogen or monovalent radicals. Polymers may also contain the hydrododecaborate group as part of the polymer chain as in polymers containing the srtuctural unit <FORM:1016379/C3/2> where W is a divalent organic radical. For linear polymers, the -O-W-O is obtained by reacting an epoxide containing two epoxide groups with H2B12H12n.H2 to open both of the epoxide groups. When the epoxide contains more than two epoxide groups cross-linking will usually result. The preferred W groups are hydrocarbon radicals, polyalkene ether radicals and fluoro-substituted alkylene radicals. An example describes the preparation of polymers of formulae:- <FORM:1016379/C3/3>ALSO:Compounds containing substituted dodecahydrododecaborate anions are made by reacting H2B12H12.nH2O with an epoxide. By varying the relative quantities of the reactants, anions are obtained having the formula [B12H12- y-(OR)y]-2, where y is an integer, generally from 1 to 4, and OR is the monovalent radical formed by the ring opening of the epoxide. Preferably an aqueous syrup of H2B12H12.nH2O is mixed with a solvent such as 1,2-dimethoxy ethane to form a solution, and an epoxide in liquid form is added slowly while maintaining the temperature so as to obtain the desired reaction rate, e.g. 10 DEG to 30 DEG C. The product may be recovered by precipitation as an insoluble salt, e.g. the cesium salt. The epoxide may contain hydrocarbon groups or one or more of the functional groups -CO.A-; -CO.OA, -CO.NA2, -CN, Cl, -C ­ C, -CHO, NO2, PO.(OA)2 -OH F1Br, -NA2, -SA, -C = CH2, -C = CH-, -CS.NA2, -SO.A, -SO2.A, -SSA, -NHCO.-OA, -NCS, -NC, where A is a monovalent organic radical, preferably hydrocarbon, of at most 18 carbons. A list of many suitable epoxides is given. Polymers containing epoxide groups may be used to produce hydrododecaborate-containing polymers. Salts corresponding to the borate anion have the formula Ma[B12H12- y(OR)y]b, where a and b are numbers of 1-3 inclusive and M is a cation, e.g. a metal, NH4+, NH2-NH3+, N-substituted ammonium, N - substituted hydrazonium, aryldiazonium, pyridinium, quinolinium, sulphonium, phosphonium, and metal ammines. Detailed examples are given.ALSO:Diborane is heated with NaBH4 in a ratio of 2: 1 in 1,2-dimethoxyethane in a sealed vessel under autogenous pressure, the white solid formed is filtered, dissolved in hot tetrahydrofuran and the solution is diluted with 1,2-dimethoxyethane and chilled to yield a solvate of disodium dodecahydrododecaborate NaB12H12.0.86C4H10O2.1.25H2O. The compound is recrystallized from a large quantity of diethyl ether or tetrahydrofuran/diethyl ether mixtures followed by drying under reduced pressure to give a monohydrate Na2B12H12.H2O or a dihydrate with less intensive drying. A solution of the dihydrate in water is passed through a column of an acidic ion exchange resin and the solution evaporated to leave a white solid residue of the formula H2B12H12.nH2O.