A fundamental understanding of reaction chemistry and pathways in fast pyrolysis of microalgae is hindered by the complex structure of proteins, lipids and carbohydrates that constitute them and the interactions among the intermediates at short timescales. In this study, bovine serum albumin (BSA), sunflower oil (SO) and potato starch (PS) were chosen as microalgae model compounds representing proteins, lipids, and carbohydrates, respectively. Fast pyrolysis of individual and binary mixtures of the model compounds was investigated at 500 °C using an analytical pyrolysis reactor interfaced with a gas chromatograph/mass spectrometer (GC/MS) and a Fourier transform infrared spectrometer (FTIR) to investigate the composition of pyrolysates and their time evolution. The composition of BSA, SO and PS was chosen to be 1 : 2, 1 : 1 and 2 : 1 (wt. basis) to emulate the microalgae composition. Fast pyrolysis of BSA : SO mixtures promoted esterification of carboxylic acids and alcohols, whereas BSA : PS and SO : PS mixtures promoted the formation of carboxylic acids via syn-elimination of esters, while inhibiting the decarboxylation pathway. The presence of SO and PS altered the pyrolysis mechanism of BSA by inhibiting the formation of aromatic hydrocarbons and nitrogen-containing compounds. The time evolution of C–H (aromatic and aliphatic), N–H, O–H, and CO stretching vibrations was monitored up to 60 s using in situ FTIR. The maximum vapor evolution time for fast pyrolysis of SO (50 s) was higher than that for BSA and PS (both 8–10 s). The addition of BSA and PS to SO increased the rate of evolution of volatiles, with the maximum vapor evolution occurring at shorter time periods. The first order apparent rate constants of fast pyrolysis followed the trend: 0.294 s⁻¹ (PS) > 0.162 s⁻¹ (BSA) > 0.107 s⁻¹ (BSA : PS (2 : 1)) > 0.073 s⁻¹ (BSA : SO (2 : 1)) > 0.048 s⁻¹ (SO : PS (2 : 1)). Fast pyrolysis char was characterized by FTIR and GC/MS, and it contained polycyclic nitrogen compounds. The plausible reactions including the interactions among the various intermediates were unraveled, and a tentative mechanism was proposed.

中文翻译：

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通过热解-GC / MS和热解-FTIR技术揭示 微藻类化合物在快速共热解中的相互作用†

对微藻快速热解的反应化学和途径的基本理解受到蛋白质，脂质和碳水化合物的复杂结构以及中间体在短时间内的相互作用的阻碍。在这项研究中，选择牛血清白蛋白（BSA），向日葵油（SO）和马铃薯淀粉（PS）作为分别代表蛋白质，脂质和碳水化合物的微藻模型化合物。使用与气相色谱/质谱仪（GC / MS）和傅立叶变换红外光谱仪（FTIR）相连的分析型热解反应器，在500°C下对模型化合物的单个和二元混合物的快速热解进行了研究，以研究热解产物的组成和他们的时间演变。选择BSA，SO和PS的组成为1：2、1：1和2：1（wt。基础上模拟微藻的组成。BSA：SO混合物的快速热解促进了羧酸和醇的酯化，而BSA：PS和SO：PS的混合物促进了羧酸的形成通过酯的同消除，同时抑制脱羧途径。SO和PS的存在通过抑制芳香烃和含氮化合物的形成而改变了BSA的热解机理。使用原位FTIR可以监测长达60 s的C–H（芳族和脂肪族），NH，OH和C O拉伸振动的时间演变。SO快速热解的最大蒸气放出时间（50 s）高于BSA和PS（均为8-10 s）。在SO中添加BSA和PS可以增加挥发物的逸出速率，而最大的蒸气逸出发生在较短的时间段内。快速热解的一阶表观速率常数遵循以下趋势：0.294 s ^-1（PS）> 0.162 s ^-1（BSA）> 0.107 s ^-1（BSA：PS（2：1））> 0.073 s ^-1（BSA：SO（2：1））> 0.048 s ^-1（SO：PS（2：1））。快速热解炭通过FTIR和GC / MS表征，其中含有多环氮化合物。阐明了包括各种中间体之间相互作用在内的合理反应，并提出了一种试探性机制。