The reaction mechanism of tetrakis hydroxymethyl phosphonium chloride(THPC) and raw collagen were researched by the simulated materials of collagen including glycin, ethylenediamine and hide powder. It was testified that THPC mainly linked with amino groups of collagen as muiltipoints and the combination mole ratio n(p)∶n(N) was 1∶2.2. The combination capacity of THPC was changed with pH and at pH 8.0 the combination amount was the highest with hydroxy and amido groups, although the reaction was weak. The 31P NMR spectrums indicated that trihydroxymethyl phosphonium hydroxide (THPOH) or trihydroxymethyl phosphine (THP) can combine with collagen. The change trends of glutin isoelectric point after treated with THPC, formaldehyde and chrome salt were researched and the results showed that the tanning property of THPC was good.
