Borate coupling agent

Fein, M.M. and Patnaik, B.K. (1978) Organic borate coupling agents, US Patent 4,073,766, Dart Industries. 

A standard official method has been published for the determination of cobalt in plant material [8 ]. The samples are digested with 1 4 v/v perchloric acidmitric acid and the residue dissolved in nitric acid. Cobalt is then extracted into chloroform as the diethyldithiocarbonate. The latter complex is decomposed by bromine and cobalt extracted into dilute hydrochloric acid. Following the addition of a borate buffer, cobalt is then extracted as the o-nitrocresol complex [9]. Excess coupling agent is removed by repeated extraction with copper acetate solution and cobalt determined spectrophotometrically at 360 nm. See Sects. 7.34.1, 7.34.3 and 7.34.4. 

Jing Dai. The synthesis and characterization of boric acid ester coupling agent and borate whisker modified polymer research. Xining Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 2006. 

In order to attain an effective flame-retardance, alumina trihydrate coupled with a halogenic agent, because of their slight synergism, is recommended. A low amount of zinc borate is also synergistic, but a greater proportion suppresses the effect (Fig. 5.5). 

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