Classes of Alcohols and Alkyl Halides

Alcohols and alkyl halides are classified as primary, secondary, or tertiary according to the classification of the carbon that bears the functional group (Section 2.10). Thus, primary alcohols and primary alkyl halides are compounds of the type RCH2G (where G is the fnnctional group), secondary alcohols and secondary alkyl halides are compounds of the type R2CHG, and tertiary alcohols and tertiary alkyl halides are compounds of the type R3CG. 

1 -Methylcyclohexanol 2-Chloro-2-methylpentane (a tertiary alcohol) (a tertiary alkyl halide) 

Classify the isomeric C4H10O alcohols as being primary, secondary,  

Many of the properties of alcohols and alkyl halides are affected by whether then-functional gronps are attached to primary, secondary, or tertiary carbons. We will see a number of cases in which a functional gronp attached to a primary carbon is more reactive than one attached to a secondary or tertiary carbon, as well as other cases in which the reverse is true. 

Write structural formulas and give the functional class and substitutive names of all the isomeric alkyl chlorides that have the molecular formula C4H9CI. 

Substitutive names are preferred, but functional class names are sometimes more convenient or more familiar and are frequently encountered in organic chemistry. 

Functional class names of alcohols are derived by naming the alkyl group that bears the hydroxyl substituent (—OH) and then adding alcohol as a separate word. The chain is always numbered beginning at the carbon to which the hydroxyl group is attached. 

The 2004 lUPAC recommendations alter the substitutive names of alcohols by bracketing the numerical locant for the substituted carbon with hyphens and placing it immediately before the -ol ending. 

Functional class name Substitutive name 2004 name  

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Section 4.2 Alcohols and alkyl halides may be named using either substitutive or functional class lUPAC nomenclature. In substitutive nomenclature alkyl halides are named as halogen derivatives of alkanes. The parent is the longest continuous chain that bears the halogen substituent, and in the absence of other substituents the chain is numbered from the direction that gives the lower number to the carbon that... 

The order of reactivity of the hydrogen halides parallels their acidity HI > HBr > HCl >> HF Hydrogen iodide is used infrequently however and the reaction of alco hols with hydrogen fluoride is not a useful method for the preparation of alkyl fluorides Among the various classes of alcohols tertiary alcohols are observed to be the most reactive and primary alcohols the least reactive... 

One way of organizing the alcohol family is to classify each alcohol according to the type of carbinol carbon atom the one bonded to the —OH group. If this carbon atom is primary (bonded to one other carbon atom), the compound is a primary alcohol. A secondary alcohol has the —OH group attached to a secondary carbon atom, and a tertiary alcohol has it bonded to a tertiary carbon. When we studied alkyl halides (Chapter 6), we saw that primary, secondary, and tertiary halides react differently. The same is hue for alcohols. We need to learn how these classes of alcohols are similar and under what conditions they react differently. Figure 10-2 shows examples of primary, secondary, and tertiary alcohols. 

Whether an alcohol is primary, secondary, or tertiary can be determined by taking advantage of the relative rates at which the three classes of alcohols react with HCl/ZnCl2. This is known as the Lucas test. The alcohol is added to a mixture of HCl and ZnCL—the Lucas reagent. Low-molecular-weight alcohols are soluble in the Lucas reagent, but the alkyl halide products are not, so the solution... 

Bhatnagar et al studied the relationship of boiling point with Vw for several classes of chemicals, including saturated alcohols, primary amines, and alkyl halides ... 

The relationship between log A ow and log S for various classes of organic compounds is shown schematically in Fig. 1, along with the ideal line for the octanol-water system. The data for organic liquids (classes 1-9) are those of Hansch et al. (44), in which most partition coefficients are calculated values. Imprecise as some of these data may be, they nevertheless form a useful basis for illustrating the characteristic behavior of organic liquids in the octanol-water system. Alcohols and ethers approach ideal behavior apparently because their structure and polarity are similar to octanol. Over the range of the solute solubility reported, the deviation of ketones, esters, alkyl halides, alkynes, and... 

This substitution reaction provides a useful general route to alkyl halides. Because halide ions are good nucleophiles, we obtain mainly substitution products instead of dehydration. Once again, the reaction rate and mechanism depend on the class of alcohol (tertiary, secondary, or primary). 

The amines are a group of compounds with the general formula R-NHj, and all the common amines are hazardous. As a class the amines pose more than one hazard, being flammable, toxic, and, in some cases, corrosive. The amines are an analogous series of compounds and follow the naming pattern of the alkyl halides and the alcohols that is, the simplest amine is methyl amine, with the molecular formula of CH NHj. Methyl amine is a colorless gas with an ammonia-like odor and an ignition temperature of 806°F. It is a tissue irritant and toxic, and it is used as an intermediate in the manufacture of many chemicals. Ethyl amine is next in the series, followed by propyl amine, isopropyl amine, butyl amine and its isomers, and so on. 

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