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Bedell, R. (1960) Interaction of boron halides with esters of phosphorous. Doctoral thesis, Northern Polytechnic.
Reactions have been carried out in the Trialkyl Phosphite - Boron Trichloride and Dialkyl Hydrogen Phosphite - Boron Trichloride systems. In the trialkyl phosphite system it was found that rapid mixed mutual replacement took place at -80° affording compounds in which the two non-metals were in different molecules. (RO)₃P + BC1₃ → (RO)₂PC1 + ROBC1₂. The second and third stage replacements were found to be very much slower. In the dialkyl hydrogen phosphite - boron trichloride system there was evidence for the formation of 1:1 complexes. These were stable at 20° when the hydrogen phosphite contained a primary alkyl group but decomposed when a secondary group e.g.,R = sec-octyl was present. All the complexes lost alkyl chloride upon being heated and the isolation of a mixture of iso- and tertiary butyl chloride from the isobutyl system,and racemised sec-octyl chloride from the (+)-sec-octyl system indicated that a carbonium ion was probably formed during the decomposition. Possible mechanisms for the decomposition are given in the Discussion. When the solid residues were heated more strongly (200°), hydrogen chloride was evolved and, after ignition in air to 1000°, the final residue was "boron phosphate". Reactions between dialkyl hydrogen phosphites and phenyl substituted boron halides at 20° were found to give solid materials after loss of alkyl halide. These solids probably contained phosphorus-oxygen-boron links and may be polymeric in character. e.g. (Et0)₂P0H + PhBC1₂ →2 EtC1 + (PhB0₂P0H)n. Diphenyl hydrogen phosphite reacted with boron trichloride to give hydrogen chloride and a new phosphorus - boron dichloride ester. (PhO)₂POH + BC1₃ →HC1 + (Ph0)₂P0BC1₂ Infra-red spectra of some of the complexes and compounds were used to determine their possible structures.
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