To implement EU REACH- (Registration, Evaluation, and Authorization of Chemicals-) like chemical legislations in various countries of which the purpose is human and environment safety, the first step is substance identification followed by the hazard and risk assessments. Although both structural and composition identifications are required, the latter can more importantly result in the essential data to fill out the required substance information such as purity and concentrations of constituents, as well as impurities. With fatty acid zinc salts (FAZSs) as an exemplary industrial chemical of which chromatographic and nuclear magnetic resonance (NMR) analyses were impossible due to their insolubility in water and any organic solvents, the composition characterization was tried by preparing their fatty acid methyl esters (FAMEs) using the conc. HCl/methanol/toluene method. This acid-catalyzed methyl esterification was optimized with zinc stearate as a surrogate substance. Gas chromatography-mass spectrometry (GC-MS) and NMR analyses on methyl-esterified products revealed that the optimum conditions were at 90°C for 10 min or 45°C for 30 min with two equivalent HCl as well as at 45°C for 10 min with five equivalent HCl. Almost all zinc stearates were converted into the corresponding fatty acids with 97–99% conversion rates. Free fatty acids (FFAs) were detected in extracted ion chromatograms of pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) in the methyl-esterified products with incomplete conversions of 73∼79%. The optimized conc. HCl/methanol/toluene method of direct one-step reaction from FAZSs was compared with the two-step NaOH saponification/BF3-methanol method after acidic hydrolysis of FAZSs. The mechanism of fatty acid zinc salts into free fatty acids and fatty acid methyl esters was suggested with the evidence of the formation of Zn(OH)2.

中文翻译：

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脂肪酸锌盐的脂肪酸甲酯的色谱和NMR光谱分析表征。

为了在旨在保护人类和环境安全的各个国家实施类似于化学品法规的EU REACH（化学品注册，评估和授权），第一步是物质识别，然后进行危害和风险评估。尽管需要结构和成分识别，但后者可以更重要地产生必要的数据，以填写所需的物质信息，例如成分的纯度和浓度以及杂质。使用脂肪酸锌盐（FAZSs）作为示例性工业化学品，由于其在水和任何有机溶剂中的不溶性而无法进行色谱和核磁共振（NMR）分析，因此通过制备其脂肪酸甲酯来尝试进行组成表征（ FAME）。HCl /甲醇/甲苯法。以硬脂酸锌作为替代物质优化了这种酸催化的甲基酯化反应。气相色谱-质谱（GC-MS）和NMR分析表明甲基化的酯化产物的最佳条件是在90°C下持续10分钟，在45°C下持续30分钟，同时加入两个当量的HCl，在45°C下进行。用五当量HCl洗涤10分钟。几乎所有的硬脂酸锌都以97-99％的转化率转化为相应的脂肪酸。在热解-气相色谱-质谱（Py-GC-MS）的萃取离子色谱图中检测到甲基酯化产物中的游离脂肪酸（FFA），其不完全转化率为73％至79％。优化浓度。将FAZSs直接进行一步反应的HCl /甲醇/甲苯方法与FAZSs酸性水解后的两步NaOH皂化/ BF3-甲醇方法进行了比较。脂肪酸锌盐转变为游离脂肪酸和脂肪酸甲酯的机理被认为是形成了Zn（OH）2的证据。