A study of the anthocyanins of kenaf
Continuing a study of the anthoeyanins [1] of the family Malvaceae , by par t i t ion chromatography on a column of ce l lu lose powder [in the w a t e r a c e t i c acid (85 : 15) system] we have isolated f rom the f lowers of Hibiscus cannabinus var . s implex (kenaf) col lected in the expe r imen ta l sect ion of the cent ra l Asian Branch of VIR ]All-Union Scientif ic R e s e a r c h Inst i tute for Plant Breeding] an anthocyanin with mp 164-166 ° C (decomp.) having the composi t ion C26H29016C 1.4H20.
Kinetics of the acetylation of e- and α-hydroxyls in cardenolides
Conclusions1.Kinetic investigations of the rate of acetylation of e- anda-hydroxy groups in cardenolides have been carried out. It has been shown that equatorial hydroxyls in aglycones acetylate more than four times as fast as axial hydroxyls.2.On the basis of the acetylation of reaction, a simple method has been proposed for determining the conformations of secondary OH groups in steroid compounds.3.The possibility has been shown of using the acetylation reaction for introducing protective groups on e-hydroxyls.
Novel method for the determination of the methoxyl content in lignin by headspace gas chromatography.
The paper reports on a headspace gas chromatographic (HS-GC) method for the determination of methoxyl in lignin. The method involves the quantitive cleavage of methoxyl with hydroiodic acid (HI) to form methyl iodide in a closed headspace sample vial at 130 °C for 30 min. After HI has been added, the sample is neutralized by injecting a sodium hydroxide solution; the methyl iodide in the vial was determined by HS-GC using a flame ionization detector. The results showed that the method has an excellent measurement precision (RSD < 0.69%) and accuracy (RSD < 3.5%) for the quantification of methoxyl content in lignin. The present method is simple and accurate and can be used for the efficient determination of methoxy1 content in lignin and related materials.