Chapter 4 Alkanes and cycloalkanes Conformations of molecules(分子 的构象
Chapter 4 Alkanes and cycloalkanes: Conformations of Molecules (分子 的构象）
4.1 Introduction of alkanes and cycloalkanes General formula chonno for alkanes C3Ha CH3CH2CH3 Propane General formula C,H2n for cycloalkanes( 烷烃) CH n2n Cyclopropane
4.1 Introduction of alkanes and cycloalkanes • General formula CnH2n+2 for alkanes • C3H8 CH3CH2CH3 Propane • General formula CnH2n for cycloalkanes (环 烷烃） • CnH2n Cyclopropane
Sources of alkanes ·4.1 A Petro|eum 4.1B Petroleum refining Table 4.1 Typical fractions obtained by distillation of petroleum Mixtures of alkanes, fortunately, are perfectly suitable for uses as fuels, solvents and lubricants, the primary uses of petroleum
Sources of alkanes • 4.1A Petroleum • 4.1B Petroleum refining • Table 4.1 Typical fractions obtained by distillation of petroleum • Mixtures of alkanes, fortunately, are perfectly suitable for uses as fuels, solvents, and lubricants, the primary uses of petroleum
41 C Cracking(裂解) When a mixture of alkanes from the gas oil C12 and higher) fraction is heated at very high temperatures(--500oC)in the presence of a variety of catalysts, the, the molecules break apart and rearrange to smaller, more highly branched alkanes containing 5-10 carbon atoms. This process is called catalytic cracking(催化裂解). Cracking can also be done in the absence of a catalyst- called thermal cracking(热裂解)
4.1 C Cracking (裂解） When a mixture of alkanes from the gas oil (C12 and higher) fraction is heated at very high temperatures (--500 oC) in the presence of a variety of catalysts, the, the molecules break apart and rearrange to smaller, more highly branched alkanes containing 5-10 carbon atoms. This process is called catalytic cracking (催化裂解）. Cracking can also be done in the absence of a catalyst--- called thermal cracking (热裂解）
2, 2, 4-trimethylpentane ( octane异辛烷) CH3 CH3 H3C—c—CH2-CH—CH3 CH3 Isooctane burns very smoothly without knocking, but heptane Burns to produce much knocking. A mixture of 87% isooctane and 13% heptane would be rated as 87-octane gasoline
2,2,4-trimethylpentane (isooctane 异辛烷) H3C C CH3 CH3 CH2 CH CH3 CH3 Isooctane burns very smoothly without knocking, but heptane Burns to produce much knocking. A mixture of 87% isooctane and 13% heptane would be rated as 87-octane gasoline