化工专业英语lesson4翻译.docx

仅供参考Introduction to Organic Chemistry1. Sources of Organic CompoundsThe major sources of organic chemicals are coal, petroleum, and agricultural products. Both coal and petroleum were formed through the geologic processes of changing animal and plant remains into carbon-containing residues. About one-third of all organic chemicals are derived from coal and about one-half from the petroleum industry有机化合物的来源有机化学药品的主要来源是煤、石油和农产品。动植物的遗体通过地质作用变成含碳残基然后形成煤和石油。三分之一的所有有机化合物品是从煤中得到的，一般来自于石油工业。2. The Methods and Objectives of Organic ChemistryBecause of the tremendous number of organic compounds known, and of the many more being synthesized daily, the study of organic chemistry is not the study of individual compounds, it is the study of groups or families of compounds all closely related to each other. Obviously, the former approach would be prohibitiveprE5hibitiv. Once the structural relationships of certain typical members of a particular group or family of compounds are understood, these structural features are understood for any one of the many members of the family, even though some may not be known compounds.因为已知的有机化合物的数目庞大，而且还在逐日合成更多的品种，所以有机化学不是研究单个的化合物，而是把彼此密切相关的化合物按类或族来研究。显然，以前的方法是不可取的，一旦典型的一类特殊化合物被认识，这些结构特征将适用于这类化合物，甚至是一些未知的化合物，For each group or family of compounds often called homologous series of compounds, structural features are important. In studying organic chemistry, it is not enough to know the identities of the elements and how many atoms of each element are present in a given molecule. More importantly, the order in which these atoms are linked together to form the molecule must also be known. Once the identities of the elements and the number of atoms present in each of these elements have been established, structural studies are quite important. They require considerable effort and ingenuity独创 on the part of the organic chemist.对于一类化合物经常称其为同系物，结构特征是非常重要的。只知道分子含有的元素和元素的原子个数是不够的，更重要的是知道原子组成分子的连接顺序，当元素及原子个数被确认之后，结构的研究也是很重要的，这些都需要有化学家的努力和聪明才智。Another important phase of the study of organic chemistry is communication, or exchange of information, among organic chemists. 学习有机化学的另一个重要的方面是有机化学家们之间交流和交换信息。This requires the acquisition of adequate vocabulary and terminology so that any one of the more than a million known compounds, or any one of the yet unsynthesized compounds, can be discussed intelligently on an individual basis.这就需要熟悉足够的词汇和术语，以便能对百万种以上已知的以及目前尚未合成的化合物中的任一化合物，逐个进行充分的讨论。This requires a highly systematized method of naming organic compounds. 这需要高度系统化的方法来命名有机化合物。This science of nomenclature命名 has received considerable attention during the development of organic chemistry, and it will constitute a second important topic for consideration in connection with each homologous series of compounds to be studied.这个科学术语在有机化学的发展过程中已经得到相当多的注意，并且他会被看做该考虑的第二个重要主题用来研究每一个同系化合物的联系。A third important topic for consideration in connection with each homologous series of compounds is procurement获得. Many organic compounds, as pointed out earlier, are naturally occurring. Many others, however, are not found in nature,and must be synthesized or prepared from compounds which can be obtained from natural sources. The term synthesis means building up of a molecule from smaller units. It is more often used, however, to mean the chemical process of changing or converting an available compound into the desired compound, either in the laboratory or on a larger scale, as in a manufacturing plant. This general topic can be described as Methods of Synthesis第三个该考虑的主题是同系物的采购。就如前面指出的，许多有机化合物在自然界中存在。但是，更多的是大自然中找不到的，必须由可以从自然资源中获得的化合物合成或配制的。这个合成的意思是从一个更小的单位构成一个分子。这个更多的是用来形容改变或转换一个可得到的化合物变成（人们）希望得到的化合物的化学反应，无论是在实验室或是在更大的范围，如在制造厂。这个主题可被描述成为“合成方法”。3. Identification of Unknown Organic Compounds The chemistry of biological systems is very complicated and the organic compounds present are numerous and constitute complex mixtures. Consequently,isolation of a pure chemical species from any one of the major sources of organic matter requires elaborate详细描述 and painstaking辛勤的 isolation procedures. Therefore, a major portion of the effort of organic chemists over the years has been devoted to improving methods for isolation and purification of organic compounds.生物化学系统非常复杂，现有的有机化合物很多并构成复杂的混合物。因此从任何一种有机物的主要来源中分离出纯化学品需要精心细致的分离程序。所以，大部分的有机化学家在努力，致力于提高有机化合物的分离和纯化方法。In summary, the following four steps are required in order to completely identify any organic compound isolated for the first time from a natural source or produced for the first time in the laboratory：(1)Isolation of the compound from the mixture of organic or inorganic compounds among which it may be found，followed by application of appropriate criteria of purity(2)Establishment of its empirical and molecular formulas by use of appropriate methods of qualitative analysis，quantitative analysis，and molecular weight determination(3)Proposal of a structural formula physical examination of the compoundas the result of appropriate chemical and(4)Synthesis of the compound