Towards the application of harvesting valuable hydrocarbon products from wastewater and associated fermentation processes, the traditional P25 Degussa TiO₂-assisted decarboxylation of simple carboxylic acid substrates - in this case acetic and propionic acids – was re-examined for its alkane production capacity. Avoiding doping or the introduction of other elements into the commercially available TiO₂ lattice, we modified other parameters of the reaction not yet explored. Under nitrogen, highly concentrated (50%) and pure (100%) solutions of both acetic acid and propionic acid demonstrated good selectivity for the decarboxylation over any other side reaction or complete mineralization, nearing or exacting a 1:1 hydrocarbon/CO₂ ratio in each case. This behaviour proves that the direct reaction of h⁺ with the acid in either case is the key parameter to favour this selectivity. In the case of acetic acid, methane’s yield was increased significantly by the periodic aeration of the catalyst when exhausted under nitrogen. The modification of solution pH to more physiological and fermentation-compatible levels (pH of 6.0) lead to improve the selectivity and the ethane’ yield in 50% propionic acid degradation and also resulted in virtually no unidentified carbon products. The Photo-Kolbe coupling and dehydration products, meanwhile, were favoured in the less concentrated solutions, suggesting that more dilute solutions may be more promising for deriving longer length hydrocarbons from substrates of smaller size. Mechanistically, these results also implicate that OH° radicals are at the origin of product generation by way of Photo-Kolbe coupling and dehydration. Finally, acetic acid and propionic acid were degraded simultaneously, in which the latter was degraded preferentially or at least initially before the former, along with the appearance of propane as a result of cross-coupling.

为了从废水和相关的发酵过程中收集有价值的碳氢化合物产品，重新检查了传统的P25 Degussa TiO ₂辅助简单羧酸底物（在这种情况下为乙酸和丙酸）的脱羧烷烃生产能力。为避免掺杂或将其他元素引入市售TiO ₂晶格，我们修改了尚未探索的其他反应参数。在氮气下，乙酸和丙酸的高浓度（50％）和纯（100％）溶液对脱羧反应的选择性高于其他任何副反应或完全矿化，接近或苛刻为1：1的烃/ CO _2。每种情况下的比率。这一行为证明了h ⁺的直接反应在任何情况下，用酸进行酸化都是支持这种选择性的关键参数。在乙酸的情况下，通过在氮气下排出催化剂进行定期曝气，甲烷的收率得到了显着提高。将溶液的pH值修改为更具生理和发酵相容性的水平（pH值为6.0）可以提高选择性和提高50％丙酸降解时乙烷的收率，并且实际上也不会产生未鉴定的碳产物。同时，Photo-Kolbe偶联和脱水产品在浓度较低的溶液中受到青睐，这表明，从较小尺寸的底物中获得较长长度的烃类，使用更多的稀溶液可能更有希望。机械上，这些结果还暗示了OH-自由基是通过光-Kolbe偶联和脱水产生产物的起源。最后，乙酸和丙酸同时降解，其中后者优先降解或至少在降解前先降解，同时由于交叉偶联而出现丙烷。