Abstract
Four kinds of the simplified methods of preparing hydroxamic acid solutions for paper partition chromatography have been devised. The methods are as follows:
Method A.-A mixture of 2_??_50mg. esters, NH2OH•HCl in absolute alcohol and sodium alcoholate is allowed to stand for 24 hours and after being acidified with HCl, it is filtered.
Method B. -A solution of 2_??_50mg. esters, NH2OH•HCI and KOH in 94% ethanol is heated at 80_??_85° for ten minutes and filtered. The filtrate is evaporated to dryness. cooled. acidified with HCl-ethanol (1:2) and filtered again.
Method C. -When free acids are used, the esters are obtained by boiling the mixture of 5_??_70mg. acids, 94% ethanol and conc. H2SO4, at 80_??_85°C for thirty minutes and after neutralization, it is treated as in the method B.
Method D. -When salts of acids are used, 10_??_100mg salts are taken and treated just as the method C.
