藻类蛋白质模型化合物苯丙氨酸的水热反应

利用石英毛细管反应器，研究了藻类蛋白质的模型化合物苯丙氨酸在水热条件下的反应特性；考察了低温段（130~220 ℃）苯丙氨酸的转化规律，并解析了苯丙氨酸在温度为220~340 ℃、反应时间为5~240 min的主要分解途径及其氮元素的转化途径和分布规律。结果表明，苯丙氨酸在130~190 ℃下转化率很低，可作为藻类水热液化过程中提取蛋白质的参考温度；在220~280 ℃下，苯乙胺是主要产物，随着反应温度升高和反应时间加长，苯乙烯产率增加。苯丙氨酸先脱羧生成苯乙胺，随着反应的加剧，苯乙胺经脱氨生成苯乙烯，苯乙烯进一步加成生成少量苯乙醇；大部分氮元素先经脱羧反应转移到苯乙胺中，进一步由脱氨反应转移到水溶性较强的NH₄⁺中。

Hydrothermal reaction of phenylalanine as a model compound of algal protein

The decomposition behavior of phenylalanine, as a model compound of algal protein, in water at high temperature was investigated in a quartz mini-batch reactor. The conversion of phenylalanine at 130~190 ℃ as well as the decomposition pathways and nitrogen transition behavior in the hydrothermal process at 220~340 ℃ with a batch holding time of 5~240 min were determined. The results showed that the conversion of phenylalanine is extremely low at 130~190 ℃, which can be used as the reference temperature for extracting high value-added protein by hydrothermal liquefaction of algae. The major product at 220~280 ℃ is phenylethylamine; however, the yield of styrene is increased with the increase of reaction temperature and holding time. In water at high temperature, phenylethylamine is obtained via decarboxylation of phenylalanine, while styrene is produced via deamination of phenylethylamine under higher temperature and longer holding time; phenylethanol is further formed via the hydration of styrene. Most of nitrogen in phenylalanine is firstly transferred into phenylethylamine via the decarboxylation of phenylalanine, and then further transferred into water-soluble NH₄⁺ via the deamination of phenylethylamine.