Aliphatic compounds Alkanes Alkenes Alkynes

Certain organic compounds contain only two elements, hydrogen and carbon, and hence are known as hydrocarbons. On the basis of structure, hydrocarbons are divided into two main classes, aliphatic and aromatic. Aliphatic hydrocarbons are further divided into families alkanes, alkenes, alkynes, and their cyclic analogs (cycloalkanes, etc.). We shall take up these families in the order given. 

Aliphatic compounds are open>chain compounds and those cyclic compounds that resemble the open chain compounds. The families we have studied so far— alkanes, alkenes, alkynes, and their cyclic analogs—are all members of the aliphatic class. 

Open-chain aliphatic hydrocarbons constitute alkanes, alkenes, alkynes, and their isomers. Alkanes have the general formula C H2 +2, where n is the number of carbon atoms in the molecnles, snch as methane, propane, n-pentane, and isooctane. Alkenes or olefins are nnsaturated compounds, characterized by one or more double bonds between the carbon atoms. Their general formula is C H2 . Examples are ethylene, 1-butene, and... 

The separation of aliphatic (e.g., alkanes, alkenes, alkynes and alcohols) and aromatic compounds (benzene) was studied using the high molecular weight... 

Scientists classify hydrocarbons as either aliphatic or aromatic. An aliphatic hydrocarbon contains carbon atoms that are bonded in one or more chains and rings. The carbon atoms have single, double, or triple bonds. Aliphatic hydrocarbons include straight chain and cyclic alkanes, alkenes, and alkynes. An aromatic hydrocarbon is a hydrocarbon based on the aromatic benzene group. You will encouter this group later in the section. Benzene is the simplest aromatic compound. Its bonding arrangement results in special molecular stability. 

In principle, the acylation of aliphatic compounds is analogous with the Friedel-Crafts acylation of aromatics in the sense that a hydrogen of the reacting alkanes, alkenes, or alkynes is replaced by an acyl group to yield ketones, unsaturated ketones, or conjugated acetylenic ketones, respectively. As discussed subsequently, however, the reactions are more complex. The acylation of aliphatics is an important but less frequently used and studied process.11-13... 

The name "aliphatic" comes from the Greek word aleiphatos, meaning "fat." Early chemists found these compounds to be less dense than water and insoluble in water, like fats. "Aliphatic" now refers to the classes of hydrocarbons called alkanes, alkenes, and alkynes. 

The compounds we have looked at so far (alkanes, alkenes, and alkynes— open chain or cyclic) are called aliphatic compounds. 

As you now know, aliphatic organic compounds belong to the alkane, alkene, and alkyne classes of compounds. Aliphatic explosives fall into both the open-chain and cycloaliphatic groups. The major sources of oxidizer in most aliphatic explosives are from the nitrate ester group (—ONO2) and the nitramine group (—NH—NO2). The nitrate esters are usually made by direct nitration of an... 

From our study so far vve know what kind of chemical properties to expect of an aliphatic hydrocarbon, that is, of an alkane, alkene, or alkyne. We know what kind of chemical behavior to expect of the parent aromatic hydrocarbon, benzene. Many important compounds are not just aliphatic or Just aromatic, however, but contain both aliphatic and aromatic units hydrocarbons of this kind are known collectively as arenes. Ethylbenzene for example, contains a benzene ring and an aliphatic side chain. 

Organic compounds that contain benzene rings as part of their structure are called aromatic compounds. The term aromatic was originally used because many of the benzene-related compounds known in the nineteenth century were found in pleasant-smelling oils that came from spices, fruits, and other plant parts. Hydrocarbons such as the alkanes, alkenes, and alkynes are called aliphatic compounds to distinguish them from aromatic compounds. The term aliphatic comes from the Greek word for fat, which is aleiphatos. Early chemists obtained aliphatic compounds by heating animal fats. 

Aliphatic hydrocarbons include three major groups alkanes, alkenes, and alkynes. Alkanes are hydrocarbons in which all the bonds are single bonds, alkenes contain a carbon-carbon double bond, and alkynes contain a carbon-carbon triple bond. Examples of the three classes of aliphatic hydrocarbons are the two-carbon compounds ethane, ethylene, and acetylene. 

Theoretical Investigations on Aliphatic Diazonium Salts, and on Alkane, Alkene, and Alkyne Diazo Compounds... 

Hydrocarbons are compounds containing only carbon and hydrogen. They are classified into aliphatic and aromatic hydrocarbons. Aliphatic hydrocarbons can be divided into three major groups - alkanes, alkenes, and alkynes. Alkanes come under saturated hydrocarbons, because they have carbon-carbon single bonds. Alkenes and alkynes are unsaturated hydrocarbons, since they have carbon-carbon double and triple bonds, respectively. 

Aliphatic compound (Section 14.1) A nonaromatic compound such as an alkane, cycloalkane, alkene, or alkyne. 

AU organic compounds are derived from a group of compounds known as hydrocarbons because they are made up only of hydrogen and carbon. On the basis of structure, hydrocarbons can be classified as aliphatic or aromatic. Aliphatic hydrocarbons do not contain the benzene group, or the benzene ring, whereas aromatic hydrocarbons contain one or more benzene rings. In addition, aliphatic hydrocarbons are further divided into alkanes, alkenes, and alkynes (Figure 16.1). 

Compound Wpes Mass values Alkanes Alkenes, Mono- cyclo- alkanes Alkynes, Dienes, Cyclo- alkenes Poly- cyclic alicycles Alkanones, Alkanals Alcohols, Alkyl ethers Cyclic alcohols Cyclo- alkanones Aliphat.. acids. Esters, Lactones Alkyl- amines... 

Most of the alkane, alkene, and alkyne compounds tested do not have SI sensitivities, except a few species such as cyclohexene and 1,3,5-cycloheptatriene. Aromatic-aliphatic hydrocarbons generate intense DSI ions with a small number of peaks, whereas polycyclic aromatic hydrocarbons (PAHs) give dominant M ... 

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