Decrease of aliphatic CHs from diatoms by in situ heating infrared microspectroscopy

作者：Alipour Leila; Nakashima Satoru^*

来源：Geophysical Research Letters, 2016, 43(8): 3670-3676.

DOI：10.1002/2016GL068638

In situ heating IR microspectroscopy at 260-300 degrees C under air and N-2 conditions has been conducted on diatom frustules to examine aliphatic CH losses during heating, simulating their changes with burial-diagenesis. Assuming a reaction model made up of two first-order kinetic relations, reaction rate constants k(1) and k(2) and activation energies (E-a) were evaluated for aliphatic CHs. The rate constants for loss of aliphatic CHs of diatom frustules under air and N-2 flow are much larger, with much smaller activation energies (57-109 kJ/mol: air; 14-44 kJ/mol: N-2), than those for conventional hydrocarbon generation reactions from kerogens (170-370 kJ/mol) studied at higher temperatures (350-450 degrees C). The CH decrease rates are somewhat different from the amide I decrease (protein degradation) rates. The obtained results suggest that organic transformation reactions including degradation of aliphatic CHs inside the diatom silica frustules might be quite different from those of kerogens separated from the biological structures.

• 出版日期2016-4-28