Hexylphosphonic acid

Rare earth elements have been enriched into a stationary phase composed of toluene including 2-ethyl-hexylphosphonic acid mono-2-ethyUiexyl ester (EHPA) from 1 L of aqueous solution and eluted with a stepwise pH gradient. As many elements remained in the column head because of their high partition coefficients to the stationary phase, they can be eluted with mobile phase and also separated mutually. 

Di-sec-butyl n-hexylphosphonate at 210-255° in a slow N2>stream with removal of the volatiles until gas evolution ceases after 17 min. n-hexylphosphonic acid (Y 90%) and butenes. F. e. A. E. Canavan, B. F. Dowden, and C. Eaborn, Soc. 1962,331. 

Dimethyl sulfoxide in acetonitrile added to an ice-cooled stirred soln. of phenyl phosphorodidiloridate in the same solvent at sudi a rate that the temp, is maintained at 15-20°, and stirring continued 1 hr. at 30-35° P, P2-diphenyl pyrophosphate. Y 84% as the bis(cyclohexylammonium) salt. - Similarly Cyclo-hexylphosphonic acid didiloride -> pi,P2.dicyciQhexylpyrophosphonic acid. Y 96% as the bis(cyclohexylammonium) salt. F. e. s. M. A. Ruveda, E. N. Zerba, and E. M. de Moutier Aldao, Tetrahedron 25, 5011 (1972). 

Forbes and Silver [40] made a systematic comparison of organic phos-phonates, phosphates and phosphinates based on the results of the 60-minute four-ball wear test under a 15 kg load at 1500 rpm. On plotting the wear data for n-butyl di-n-octylphosphinate, di-n-butyl n-hexylphosphonate, di-n-butyl phenylphosphonate, diethyl benzylphos-phonate, diethyl o-nitrophenylphosphonate and tri-n-butyl phosphate against the ionization constants of the corresponding parent acids (expressed as pK ), the solid curve of Fig. 11-10 was obtained. This led them to the hypothesis that the involvement of carbon-phosphorus bonding... 

Figure 11-10. Comparison of organic phosphates, phosphonates and phos-phinates as lubricant additives. Four-ball test 60 minutes, 15 kg load, 1500 rpm. 4 mmoles of additive per 100 gm of white oil solution. Neutral esters o. Acids or acid esters A. 1 n-Butyl di-n-butylphosphinate. 1 Di-n-hexylphosphinic acid, la Di-n-octylphosphinic acid. 2 Di-n-butyl n-hexylphosphonate. 3 Di-n-butyl phenylphosphonate. 4 Tri-n-butyl phosphate. 4 Di-n-butyl phosphate. 5 Diethyl benzyIphosphonate. 6 Diethyl o-nitrophenylphosphonate. 7 Di(2-ethylhexyl) phosphate. 8 Dilauryl phosphate. 9 Tricresyl phosphate. From data by Forbes and Silver [40] and by Forbes and Battersby [46].

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