日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 B (地球生命科学) » B-BC 生物地球化学

[B-BC03] 生命-水-鉱物-大気相互作用

2019年5月28日(火) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:掛川 武(東北大学大学院理学研究科地学専攻)、横山 正(広島大学大学院総合科学研究科)、福士 圭介(金沢大学環日本海域環境研究センター)、白石 史人(広島大学大学院理学研究科地球惑星システム学専攻)

[BBC03-P04] CO 大気の光化学で生じるグリオキシル酸

*磯田 健太1蔵 暁鳳1上野 雄一郎1,2 (1.東京工業大学 理学院 地球惑星科学系、2.東京工業大学 地球生命研究所)

キーワード:大気、光化学

Glyoxylate could be an important compound, which can initiate a simple autocatalytic cycle and may possibly evolve to synthesize amino acids, nucleobase, pentose etc. (Eschenmoser, 2007a). However, constant supply of glyoxylate is an issue for the prebiotic environment. In this study, we aim to understand the possible condition to supply glyoxylate continuously to support such an autocatalytic cycle. First, we have performed experimental study and demonstrated that glyoxylic acid can be synthesized photochemically under carbon monoxide atmosphere. On the other hand, the UV irradiation into formaldehyde solution does not yield glyoxylic acid, except for the presence of CO in the gas phase. These results indicate that glyoxylate is not produced from formaldehyde in solution but from CO in the gas phase probably through the 3 steps: (i) HCO radical is produced from the reaction between CO and H from H2O photolysis; (ii) The HCO radical dimerize in the gas phase, to form (CHO)2(glyoxal); and (iii) The (CHO)2 is oxidized into HCOCOOH (glyoxylate). An additional experiment demonstrated that UV irradiation into pure glyoxal solution can yield glyoxylate, and thus indicate that the step (iii) can proceed in the solution. Consequently, our experimental results suggests that glyoxylate can be continuously provided from atmosphere into hydrosphere if the atmosphere is rich in CO.