The total organic carbon of carbonate sediments includes a 5%–45% contribution from acid-soluble organic matter, particularly carboxylic acid salts. However, there is little information available on hydrocarbon generation from carboxylic acid salts. The objectives of this study were to investigate the extent and timing of hydrocarbon generation from calcium stearate. Thus, gold-tube nonhydrous pyrolysis experiments of calcium stearate were conducted from 250 to 600 °C at 50 MPa. Infrared spectroscopy and δ¹³C testing were also performed on solid pyrolysate and gaseous products, respectively, to trace changes of functional groups and stable carbon isotopes.

Pyrolysis of calcium stearate produced hydrocarbons, CO₂, CaO, CaCO₃, coke, and other inorganic compounds of low molecular weight. A Van Krevelen diagram indicated that calcium stearate falls in the same region as hydrogen-rich type I kerogen. The maximum yield of methane generated from calcium stearate was as high as that from North Sea oil. Hydrocarbon generation from calcium stearate was related to cracking of the alkyl moiety and similar to that occurring in pyrolysis of n-C₁₈. As a consequence of kinetic carbon isotope fractionation, with increasing temperature CO₂ becomes enriched in ¹³C and CaCO₃ becomes enriched in ¹²C. Notably, CaCO₃ with very low δ¹³C values is probably an effective proxy indicating hydrocarbon generation from carboxylic acid salts, if no other CaCO₃ is produced via thermochemical sulphate reduction processes. The optimized kinetic parameters demonstrate that calcium stearate had higher methane generation activation energies than those of n-C₁₈ and type I kerogen. Hence, methane generation from calcium stearate is delayed when extrapolated to geological conditions. This retarded methane generation illustrates the vital role of carboxylic acid salts in the generation of deep oil and gas. Future research should concern the abundance of carboxylic acid salts in carbonate formations and the depositional environments that facilitate the formation of carboxylic acid salts.

碳酸盐沉积物的总有机碳包括5％至45％的酸溶性有机物，特别是羧酸盐。然而，关于由羧酸盐产生烃的信息很少。这项研究的目的是调查硬脂酸钙生成烃的程度和时间。因此，硬脂酸钙的金管无水热解实验是在250至600℃，50 MPa下进行的。红外光谱和δ ¹³还对热解固体和气态产物，分别进行肝炎测试，追踪官能团和稳定碳同位素的变化。

硬脂酸钙的热解产生烃，CO ₂，CaO，CaCO ₃，焦炭和其他低分子量无机化合物。Van Krevelen图表明硬脂酸钙与富氢I型干酪根在同一区域。硬脂酸钙产生的甲烷最大产率与北海石油产生的甲烷一样高。由硬脂酸钙产生的烃与烷基部分的裂解有关，并且与在正碳_18的热解中发生的类似。动态碳同位素分馏的结果是，随着温度的升高，CO ₂富含¹³ C，CaCO ₃富含^{12 C}C.值得注意的是，碳酸钙₃以非常低的δ ¹³ C值可能是指示从羧酸盐烃类生成一个有效的代理，如果没有其他的CaCO ₃经由热化学硫酸盐还原过程产生的。优化的动力学参数表明，硬脂酸钙具有比n -C ₁₈更高的甲烷生成活化能。和I型干酪根 因此，当推断到地质条件时，硬脂酸钙的甲烷产生被延迟。甲烷的这种延迟生成说明了羧酸盐在深层石油和天然气生成中的重要作用。未来的研究应关注碳酸盐岩层中羧酸盐的丰富性以及有助于形成羧酸盐的沉积环境。