- 更多网络例句与醛式合物相关的网络例句 [注:此内容来源于网络,仅供参考]
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The results of in situ DRIFTS on propylene oxidation show that the allyl species originated from α-H abstraction of propylene were located at the wavenumbers of 1454 cm~(-1) and 1427 cm~(-1). The rate-determining step is the abstraction of an α-H abstraction from a lattice oxygen linked to a bismuth ion to form a π-allyl intermediate coordinated to a molybdenum ion. The metal-oxo group then attacks the allyl intermediate forming a σ-bonded oxygen-allyl species, which is in a rapid equilibrium with the π- bonded species. The σ-bonded species then transforms to acrolein by further abstraction of α-H. Such species as formate, carboxylate, carbonate transform to deep oxidation products. The acetone was derived from propylene by an enolic species at lower temperatures.
丙烯氧化反应体系的原位漫反射红外光谱研究结果表明,由丙烯脱氢生成的烯丙基中间物种吸收峰在1454cm~(-1)和1427cm~(-1)处;基于此提出了较完整的丙烯氧化反应网络:丙烯选择氧化生成丙烯醛主要经历丙烯脱除甲基上的一个H,生成烯丙基物种,该物种嵌氧生成σ-O络合物,脱氢得到丙烯醛前驱体,脱附生成丙烯醛;完全氧化产物是由催化剂表面上生成甲酸盐、羧酸盐、碳酸盐等形式的中间物种转化而成;较低反应温度下丙烯氧化生成丙酮,通过烯醇式中间物种氧化生成丙酮前驱体得到。
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Such structural complexity is further enhanced by O-acetylation, esterification, lactonization, as well as other forms of substitutions, reflecting significance of carbohydrates in cell recognition.
细胞表面上糖缀合物的糖链经常以多/寡聚体形式存在,并且结构复杂,常常大量表达唾液酸、糖醛酸、硫酸化糖基等酸性糖,并发生O-乙酰化、酯化和内酯化等修饰。