4-(9,10-Dioxo-9,10-dihydro-anthracen-1-yl)-4-oxobutanoic acid.

In the title compound, C(18)H(12)O(5), the anthracene moiety is almost planar (r.m.s. deviation = 0.0399 Å). In the crystal, mol-ecules are linked to each other by inter-molecular O-H⋯O and weak C-H⋯O hydrogen bonds.

[Study on the function group uniformity of polystyrol sulfonyl chloride resins by infrared spectra].

The reactions of polyvinyl benzene with chlorosulfonic acid were performed under different ratio and reaction time and the results of chloro-sulfonation were detected by infrared spectrometer (380FT-IR). The characteristic peak at 1 601.5 cm(-1) belongs to benzene ring and was selected as the internal standard peak Two characteristic peaks at 1 377.4 and 3 476.8 cm(-1) were selected as reference peaks, and belong to sulfonyl chloride and sulfonic group respectively. According to the Lambert-Beer law, the absorbance at 1 377. 4 and 3 476.8 cm(-1) was detected and compared with absorbance at 1 601.5 cm(-1) respectively. The value of A1 377.4 : A3 476.8 was used to express uniformity of polystyrol sulfonyl chloride resins. The results show that: (a) After 0.5 h, A1 377.4 : A1 60.5 rises quickly with the prolonging of reaction time; and A3 476.8 : A1 601.5 rises too, but descends after 1 h. And the value of A1 377.4 : A3 476.8 rises with the prolonging of reaction time after 1 h. (b) When the ratio of HSOs Cl and PS is less than 1 : 1, A3 476.8 : A1 601.5 rises with the ratio increasing, but when the ratio of HSO3 Cl and PS is more than 1 : 1, A3 476.8 : A1 601.5 descends while A1 377.4 : A1 601.5 appears and increases following the increase in the ratio. As the ratio was 4 : 1, A1 377.4 : A 601.5 and A3 476.8 : A, 601.5 show stabilization. In one step reaction condition, as the ratio of HSO3 Cl and PS is 4 : 1, the reaction can enhance uniformity of PS-SO2 Cl at 60 degrees C for 5 h (the loading of sulfonyl chloride is 4.0 mmol x g(-1)). It was also confirmed that the function group uniformity of polystyrol sulfonyl chloride resins could be determined by infrared spectroscopy conveniently and quickly. Meanwhile, this method could be adopted to determine the function group uniformity practicably and widely.

[Determination of the content of poly (lactic acid-co-phenylalanine) by infrared spectroscopy].

To improve the thermal stability of poly (lactic acid), poly (lactic acid-co-phenylalanine) was prepared by introducing the phenyl of phenylalanine to the side chain. 3-phenylmethyl-2,5-morpholinedione (PMD) and lactide (LA) were synthesized using phenylalanine and lactic acid as raw materials, respectively. Subsequently, poly (lactic acid-co-phenylalanine), homopolymer of PMD (PPMD) and homopolymer of LA (PLA) were obtained by ring-opening polymerization of PMD and LA as monomer. The amount of phenyl had an effect on the thermal stability, so a quantitative analysis by infrared spectroscopy was established in the present paper. Two homopolymers were determined by infrared spectroscopy to find out two characteristic peaks at 1 671.53 and 870.82 cm(-1), which were selected for PPMD and PLA, respectively. Choosing the characteristic peaks and according to the Lambert-Beer law, which is the linear relationship between absorbance and concentration of an absorbing species, a standard working curve was calculated: y = 0.055 67x + 0.109 1 (r = 0.999 3), where x was the reciprocal of PPMD monomer molar concentration and y was the absorbance ratio of PLA to PPMD at their characteristic peaks. Collecting the absorbance of poly (lactic acid-co-phenylalanine) at two characteristic peaks, the contents of copolymer were calculation by the working curve and the results were similar to that of 1H NMR by calculation from the ratio of proton area of PMD and PLA. It was noted that the relative error was below 2%. It was also confirmed that the content of copolymer could be determined by infrared spectroscopy conveniently and quickly. Meanwhile, this method could be adopted to determine the other poly (lactic acid-co-amino acid) practicably and widely.