Wednesday, January 5, 2011

HALPHEN-HICKS TEST

Boli a little cloth with a solution of (1 part phenol, 2 parts carbon tetrachltide)
settle, pour bromine  vapour on to the surface: colora- tion (varuing according to
the ptoduct) indicates resin oils.
PHENOLS (a) Heat a little cloth with 1 gm. phthalic anhydride containing 2-3
drops of conc. sulphuric acid until a rich brown melt is obtained. Cool, dilute
with water , make alkaline with NaOH : pink indicates phenols.
(B) boil a little cloth or resin with 5 c.c. water containing 1 drop conc. H2SO4
cool, add a few drops of carbazole (1-2% in 95% ethyl alcohol ) and 1-2 drops of
conc. H2SO : blue indicates phenol/formaldehyde resin. (C) place a litle cloth on
a spotting plate, add one or two drops conc. HCI< then 1 drop of phenol- cresol
bodies.
The test may be used on resin solution . (D)see test 21 (indophenols).

DETERGENTS AND WETTING AGENTS :


This group of bodies include true sopas, sulphonated castor-oil sops, sulphonated and sulphated fatty alcohols, synthetic detergents, quaternary compounds, and saponins, with which may be incorporated solvents, alkalis, disinfectants, builders, or oxidising agents. The  prooery which they have in common is the power to wet dirt oils and fats and textile fibers ;
detergent power is a property which may be regarded as wetting agents for oils and waxes, though their simplle action is probably merely one of blending with the fatty body , reducing its melting point and viscosity, and waxes, thereby making emulsification mechanically easier. If the wetting solvent is polar in character it may most also act as a bridge between the fat and deter-gent molecules.
The most common solvents are carbon tetrachloride, trichlorethylene, pyridine, cyclohexanol, pine oil, and in stringly alkaline liquors, cresylic acid .(continue)


No comments:

Post a Comment