hemiacetal

简明释义

英[ˌhemiəˈsiːtæl]美[hemɪˈæsɪtæl]

n. （化）半缩醛

英英释义

单词用法

同义词

反义词

例句

1.These compounds are soluble in water, and contains the hemiacetal hydroxyl free, so in alkaline solution can reduce silver ions and copper ions.

这些化合物能溶于水，并含有游离的半缩醛羟基，所以在碱溶液中能还原银离子和铜离子。

2.These compounds are soluble in water, and contains the hemiacetal hydroxyl free, so in alkaline solution can reduce silver ions and copper ions.

这些化合物能溶于水，并含有游离的半缩醛羟基，所以在碱溶液中能还原银离子和铜离子。

3.When glucose dissolves in water, it exists predominantly as a hemiacetal 半缩醛 form.

当葡萄糖溶解在水中时，它主要以hemiacetal 半缩醛的形式存在。

4.In the presence of acid, a hemiacetal 半缩醛 can easily convert back to its original aldehyde.

在酸的存在下，hemiacetal 半缩醛可以很容易地转回其原始的醛。

5.In organic chemistry, a hemiacetal 半缩醛 is formed when an aldehyde reacts with an alcohol.

在有机化学中，当醛与醇反应时，会形成一个hemiacetal 半缩醛。

6.A hemiacetal 半缩醛 can undergo further reaction to become a full acetal.

一个hemiacetal 半缩醛可以进一步反应成为一个完全的缩醛。

7.The formation of a hemiacetal 半缩醛 can be reversible, depending on the conditions.

一个hemiacetal 半缩醛的形成可以是可逆的，这取决于条件。

作文

In the world of organic chemistry, understanding the various functional groups and their transformations is essential for grasping the complexity of molecular interactions. One such important class of compounds is the hemiacetals. A hemiacetal is formed when an alcohol reacts with an aldehyde or a ketone, leading to a compound that contains both an alcohol and an ether functional group. This reaction is crucial in many biological processes and synthetic pathways. The formation of a hemiacetal can be illustrated by considering the reaction between ethanol and an aldehyde, such as formaldehyde. When these two react, the hydroxyl group (-OH) from the ethanol attaches to the carbon atom of the aldehyde, while the hydrogen atom from the aldehyde's carbonyl group is released. The resulting structure features a carbon atom bonded to both an -OH group and an -OR group (where R represents the alkyl group from the alcohol). This dual functionality gives the hemiacetal unique properties compared to its parent aldehyde or ketone. One of the fascinating aspects of hemiacetals is their equilibrium with their corresponding aldehydes or ketones. In aqueous solutions, hemiacetals can readily interconvert with their starting materials, making them dynamic and versatile. This equilibrium plays a significant role in biological systems, especially in carbohydrate chemistry. For instance, sugars often exist in cyclic forms known as pyranoses and furanoses, which are essentially hemiacetals. The ability to form and break down these structures allows for the complex regulation of metabolic pathways. Furthermore, hemiacetals serve as intermediates in the synthesis of more complex molecules. They can undergo further reactions to form acetals, which are more stable than hemiacetals and do not readily revert to their aldehyde or ketone forms. This stability is particularly useful in organic synthesis, where chemists often aim to protect reactive functional groups during multi-step reactions. By converting an aldehyde into a hemiacetal and then into an acetal, chemists can effectively safeguard the molecule from unwanted reactions. In conclusion, the study of hemiacetals is not only vital for understanding fundamental organic chemistry but also for appreciating the intricate nature of biological systems and synthetic methodologies. Their unique characteristics and reactivity make them indispensable in the toolbox of chemists and biochemists alike. As research continues to evolve, the role of hemiacetals in various chemical processes will undoubtedly expand, revealing even more about the fascinating world of molecular chemistry.

在有机化学的世界中，理解各种功能团及其转化对于掌握分子相互作用的复杂性至关重要。其中一个重要的化合物类别是半缩醛。半缩醛是在醇与醛或酮反应时形成的，导致含有醇和醚功能团的化合物。这种反应在许多生物过程中和合成路径中至关重要。半缩醛的形成可以通过考虑乙醇与醛（如甲醛）之间的反应来说明。当这两者反应时，乙醇中的羟基（-OH）附着到醛的碳原子上，而醛的羰基上的氢原子被释放。生成的结构具有一个碳原子，同时与一个- OH基团和一个- OR基团（其中R代表醇中的烷基）相连。这种双重功能使得半缩醛与其母体醛或酮相比具有独特的性质。半缩醛的一个迷人方面是它们与其对应的醛或酮之间的平衡。在水溶液中，半缩醛可以轻易地与其起始材料相互转化，使其动态而多样。这种平衡在生物系统中发挥着重要作用，尤其是在碳水化合物化学中。例如，糖通常以称为吡喃糖和呋喃糖的环状形式存在，这本质上就是半缩醛。形成和破坏这些结构的能力使得代谢途径的复杂调控成为可能。此外，半缩醛在合成更复杂分子的过程中作为中间体。它们可以进一步反应形成比半缩醛更稳定的缩醛，后者不容易恢复成醛或酮。这种稳定性在有机合成中尤为有用，化学家们常常希望在多步反应中保护反应性功能团。通过将醛转化为半缩醛，然后转化为缩醛，化学家们可以有效地保护分子免受不必要的反应。总之，研究半缩醛不仅对理解基本有机化学至关重要，而且对欣赏生物系统和合成方法的复杂性也同样重要。它们独特的特性和反应性使其在化学家和生物化学家的工具箱中不可或缺。随着研究的不断发展，半缩醛在各种化学过程中的作用无疑会扩展，揭示出分子化学迷人世界的更多内容。