有机化合物简介（英文）——organic compounds1

organic compounds hydrocarbons

organic compounds ——hydrocarbons

u The term organic appears to have been used for the first time about 1777 and was applied to those materials occurring in or derived from living organisms. Accordingly, such substances as starch alcohol, and urea were classified as organic, for starch is produced by living plants, alcohol is a product of fermentation caused by microorganisms, and urea is contained in urine. In 1824. however the German chemist WOhler synthesized urea, and the original meaning of the term"organic"no longer applied Organic compounds, in the modern sense, are the compounds of carbon. Many thousands of carbon compounds which are not found in or derived from living organisms have been produced by chemists, and well over a million organic compounds are already known

◼ The term "organic" appears to have been used for the first time about 1777 and was applied to those materials occurring in or derived from living organisms. Accordingly, such substances as starch, alcohol, and urea were classified as organic, for starch is produced by living plants, alcohol is a product of fermentation caused by microorganisms, and urea is contained in urine. In 1824, however, the German chemist WÖhler synthesized urea, and the original meaning of the term “organic” no longer applied. Organic compounds, in the modern sense, are the compounds of carbon. Many thousands of carbon compounds which are not found in or derived from living organisms have been produced by chemists, and well over a million organic compounds are already known

The existence of so many organic compounds is due primarily to the ability of carbon atoms to combine with other carbon atoms, forming chains of different lengths and rings of different sizes. The elements, other than carbon, most frequently found in organic compounds are hydrogen, oxygen, nitrogen, sulfur, the halogens, phosphorus, and some of the metals. Although the number of organic compounds is vast, the study of organic chemistry is greatly simplified by the fact that the chemistry of carbon compounds can be organized around"functional groups", each of which imparts similarities in chemical properties

The existence of so many organic compounds is due primarily to the ability of carbon atoms to combine with other carbon atoms, forming chains of different lengths and rings of different sizes. The elements, other than carbon, most frequently found in organic compounds are hydrogen, oxygen, nitrogen, sulfur, the halogens, phosphorus, and some of the metals. Although the number of organic compounds is vast, the study of organic chemistry is greatly simplified by the fact that the chemistry of carbon compounds can be organized around “functional groups”, each of which imparts similarities in chemical properties

Hydrocarbons The simplest organic compounds are those containing only carbon and hydrogen. Such compounds are known as hydrocarbon. Some of them are found in nature, where they were derived from plant or animal forms of life Several types of hydrocarbons are possible

Hydrocarbons ◼ The simplest organic compounds are those containing only carbon and hydrogen. Such compounds are known as hydrocarbon. Some of them are found in nature, where they were derived from plant or animal forms of life. Several types of hydrocarbons are possible

The alkanes The series of compounds which have the general empirical formula CnH2n+2, where n is an integer, is called the alkane, or paraffin The lighter members of the alkane series are gases, the members of intermediate weight are liquids, and the heavier members are solids. From the formulas of the compounds it is evident that each member differs from the preceding one by the increment CH2. A series of compounds in which each member differs from the one before it by a common increment is called a homologous series

The alkanes ◼ The series of compounds which have the general empirical formula CnH2n+2, where n is an integer, is called the alkane, or paraffin. ◼ The lighter members of the alkane series are gases, the members of intermediate weight are liquids, and the heavier members are solids. From the formulas of the compounds it is evident that each member differs from the preceding one by the increment CH2 . A series of compounds in which each member differs from the one before it by a common increment is called a homologous series

The electronic formulas for methane ethane, and propane are easily written Although the electronic formula representation makes the molecules seem planar, it must be remembered that in all the alkanes the c-c and c-h bonds have the geometrical arrangement set b the tetrahedral configuration of each carbon unI

The electronic formulas for methane, ethane, and propane are easily written. Although the electronic formula representation makes the molecules seem planar, it must be remembered that in all the alkanes the C—C and C—H bonds have the geometrical arrangement set by the tetrahedral configuration of each carbon unit

H Methane Pentane

Methane Pentane

There are two hydrocarbons having the formula 4H10, and these are known as normal butane and isobutane. The two butanes are isomers. They have the same empirical formula, and hence the same composition, but different physical and chemical properties, because they differ in the arrangement of the atoms in their molecules. normal butane. n butane, is astraight chain?molecule and isobutane isa“ branched chain” molecule. The number of possible isomers increases with increasing molecular weight; the hydrocarbon of large molecular weight have great numbers of isomers

There are two hydrocarbons having the formula C4H10, and these are known as normal butane and isobutane. The two butanes are isomers. They have the same empirical formula, and hence the same composition, but different physical and chemical properties, because they differ in the arrangement of the atoms in their molecules. Normal butane, n￾butane, is a “straight chain” molecule and isobutane is a “branched chain” molecule. The number of possible isomers increases with increasing molecular weight; the hydrocarbon of large molecular weight have great numbers of isomers

Alkanes are characterized by being rather unreactive chemically; hence, the use of the name parafin, which means"having little affinity". The following reaction is a typical one for the alkanes and is referred to as a substitution reaction,(heat or UV light) CH4+CI=CH3Cl+HCI

Alkanes are characterized by being rather unreactive chemically; hence, the use of the name paraffin, which means “having little affinity”. The following reaction is a typical one for the alkanes and is referred to as a substitution reaction. (heat or UV light) CH4+Cl2=CH3Cl+HCl

This reaction is a chain reaction which proceeds in several steps. An important point concerning this particular reaction is that it transforms an alkane molecule into one which has a more reactive“ functional group” on it-a halogen in this specific case. The functional group makes it possible for the molecule to take part in many different kinds of reactions

This reaction is a chain reaction which proceeds in several steps. An important point concerning this particular reaction is that it transforms an alkane molecule into one which has a more reactive “functional group” on it——a halogen in this specific case. The functional group makes it possible for the molecule to take part in many different kinds of reactions