Motohisa Furusawa

Thin-layer chromatography of the linear oligomers of ethylene terephthalate

Abstract A method for the qualitative and quantitative analysis of the linear oligomers of the ester-diol type and ester-hydroxy acid type from ethylene terephthalate is described. As thin-layer chromatographic solvent systems, a chloroform-ethanol (9: i ) system is suitable for the separation of the oligoesters of the eser-diol type and a n -propanol-28% aqueous ammonia-water (70:25:5) system for the ester-hydroxy acid type. Oligoesters separated on the thin-layer chromatographic plate were sprayed with a hydroxylamine solution and then with a ferric perchlorate solution, so that purpose chelate complexes wee formed. Quantitative analysis was carried out by lifting the spots from the plate, reacting them again with the same two solutions, and, after filtration, measuring the absorption of the solution at 540 nm. The average recovery was 97%. The method could decrease the experimental errors caused by scraping off the spots, because visible spots were scraped and unreacted samples were again reacted with the same reagents.

Determination of Melamine in Benzoguanamine by Cation Exchange Chromatography

Amethod fo the determination of small amounts of melamine presen, t as an impurity in benzoguanamine is proposed. Melamine can be separated from ben2oguanamine by a ion exchange chromatography using a 8 250 mm co1umn packed with a strongly-acidic cation exchanger, AG 50 W-X 4. About 10 mZof the solution containing 50 mg of the sample in O.04mol hydrochloric acid is passed through the co1umn. After eluting interfering impurities with 170to 190 ml of O.8 mol/l hydrochloric acid at 35, melamine is eluted quantitatively with 20 ml of the same eluent. Melamine is determined by the measurement either the absorbance of the eluted, so1uton mad P to a certain volumeor the peak area of the chromatogram. The absorbance is measured by the difference between the absorption at 235 and 250 nm, and the chromat ogram is obtained by continuous measurement of the absorbanceof the emuent at 235 nm. Melamlne in benzoguanamine can be determined down to O, 1%, This method is nQt interfered by the presence of impurities such as cyanomelamine and ammeline.

Determination of Trace Amounts of Anthracene in Anthraquinone by Ultraviolet Spectrophotometry

An ultraviolet spectrophotometric method for the determination of trace amounts of anthracene in anthraquinone is studied. The method is based on that anthracene is separated by extraction with n-heptane after the sample is reduced and dissolved with sodium hydrosulfite alkaline aqueous solution. One gram of sodium hydrosulfite, 30 ml of 0.5 mol/l sodium hydroxide solution and 100 mg of the sample are added into 50 ml separating funnel. The air in the funnel is replaced with nitrogen. The solution is warmed to 45° C and shaken until anthraquinone is dissolved. After 15 ml of n-heptane is added, the mixture is shaken sufficiently, and then the aqueous phase is removed. To remove the remaining anthraquinone, n-heptane phase is shaken once more with 30 ml of sodium hydroxide solution containing 300 mg of sodium hydrosulfite. Anthracene is determined by the difference between the absorbance at 375 nm and that at 385 nm.

Determination of Methacrylic Acid in Synthetic Process of Methyl Methacrylate

メタクリル酸メチルモノマーの製法として現在行われている一般的方法は, Rohm&Haas法である。この合成過程中ではメタクリル酸アミドが加水分解してメタクリル酸が生成しているので, この合成過程を検討するためにメタクリル酸の定量法が必要となる。合成過程中には多量の共存物質が存在し, これらの影響を受けることなく, メタクリル酸を定量する方法は従来なく, この面における合成過程の検討は行うことが出来なかった。著者らはメタクリル酸のアルカリ滴定を行う際, 滴定に妨害を与える物質を蒸留によって釜残として残存させ, 水とともに定量的に留出したメタクリル酸をアルカリ滴定で求める分析方法を考案確立した。すなわち, 試料をアルカリで中和した後メタクリル酸アミドの加水分解を防ぐために酒石酸を添加して酸性となし, 更にメタクリル酸の留出速度を大きくするために硫酸ナトリウムを加えて蒸留を行い, メタクリル酸を水とともに留出させ, これをアルカリ滴定する方法である。