优选了从青蒿母液中提取青蒿酸(1)和二氢青蒿酸(2)的工艺.以1、2提取率为筛选指标,以乙醇萃取温度、碳酸氢钠溶液用量、乙醇浓度和氢氧化钠溶液浓度为考察因素,用L9(34)正交试验优选最佳提取工艺.结果1、2提取最佳工艺参数为乙醇浓度80％,萃取温度15℃,碳酸氢钠溶液用量20 ml,氢氧化钠溶液浓度3％,1、2提取率为31.0％和30.5％,所得样品纯度大于98％.

A new method,based on the composite application of the iterative algorithm,the partial least squares(PLS) and the ultraviolet spectrophotometry,was presented for the simultaneous determination of three tolualdehyde isomers among the six components prepared by indirect electrosynthesis with the xylene.The PLS was enchased to the iterative algorithm to obtain the approximation through the interactive calculations,which could improve the spectral identification ability of the products.The proposed method was applied in the simultaneous determination of three tolualdehyde isomers in four simulating samples with satisfactory results.The mean recoveries of o-tolualdehyde,m-tolualdehyde and p-tolualdehyde were 101%,100% and 101%,respectively,and root mean square errors of prediction(RMSEP) were 0.214,0.148 and 0.057,respectively.The practical application to five group electrosynthesis tolualdehyde products showed that the average recoveries were 106%,92% and 100% for o-tolualdehyde,m-tolualdehyde and p-tolualdehyde,respectively,and the relative error was less than 19.7%.The results were compared with those obtained from the HPLC method with no significant difference.

Chemometrics was the chemical measured technique developing quickly in recent years. Methods which be used commonly include wavelet transform, multiple linear regression, partial least square, principal component analysis, artificial neural network and genetic algorithm and so on. The combination of spectrophotometry with chemometrics was widely used in various fields, such as industry, agriculture and environment monitoring. It reflected an important role of chemometrics in data processing, analytic signal and so on. The establishments of chemometrics- spectrometry provide an effective way for rapid and accurate determination of mixture and meet the quality control demands in the industry and agriculture.

The refinement of 3,5-cresol by fractional crystallization was studid.The content of 3,5-cresol was up to 98.0%,and the crystallization yield was 44.0%.

In this paper, step crystallization of 3,4-dimethylphenol was studied to give 3,4-dimethylphenol (≥98.0%). The effects of step crystallization were studied for optimizing the crystallization conditions, then the conditions with high yield and low cost were successfully applied in the test, the yield of 3,4-dimethylphenol reached 44.0%.