1-4 of 4 Results

  • Keywords: halogenoalkanes x
Clear all

Chapter

Cover Chemistry3

Halogenoalkanes  

Substitution and elimination reactions

This chapter begins with an overview of the structure and reactivity of halogenoalkanes, followed by a discussion of the most important methods of preparing these compounds. Halogenoalkanes are particularly useful intermediate compounds in organic synthesis as they react with nucleophiles and as bases to form valuable products and bases in elimination reactions, which is an important way of making alkenes. The chapter explains why different carbon–halogen bonds in halogenoalkanes react differently from one another. It details how halogenoalkanes react in SN1, SN2, E1, E2 reactions, including factors that affect SN2 versus SN1 reactions and factors that affect E2 versus E1 reactions. The factors that influence substitution versus elimination reactions are also covered.

Chapter

Cover Making the Transition to University Chemistry

Alcohols  

This chapter focuses on alcohols (ROH) which have at least one hydroxyl group bonded to a carbon atom. Alcohols are known to undergo two reactions similar to the reactions of halogenoalkanes. Additionally, esters are formed through an alcohol's reaction to carboxylic acids. Alcohols also undergo oxidation reactions. The chapter explores the main manufacturing processes for ethanol which are fermentation and the direct hydration of ethene. It also considers the nucleophilic substitution and oxidation reactions of alcohols. The elimination reactions coincide with alcohol being dehydrated through heating with acid. However, conditions depend on the specific alcohol involved in the process as some of the alcohols could produce more than a single product.

Chapter

Cover Making the Transition to University Chemistry

Halogenoalkanes  

This chapter explains the concept of halogenoalkanes which have carbon-halogen bonds which are significantly polar. However, the carbon atom is partially positively charged and susceptible to a nucleophilic attack. The chapter explains that carbon-halogen bond enthalpy determines the relative rate of reaction. The three common nucleophilic substitution reactions of halogenoalkanes involve sodium hydroxide, potassium cyanide, and ammonia. Elimination is the second vital characteristic type of reaction of halogenoalkanes as it produces an alkene. The hydroxide ion is acting as the base of the compound rather than a nucleophile. Elimination is favoured over substitution where we see nucleophiles with strong bases, bulky nucleophiles, and high temperatures.

Chapter

Cover Foundations of Organic Chemistry: Worked Examples

Reactions with nucleophiles  

This chapter explores the nature and distinction of bases and nucleophiles, including interconversions and synthesis. It discusses reactions of halogenoalkanes by bimolecular processes. Here it covers the mechanism, transitions state, energy profile, stereochemistry, and competition with elimination. It also talks about the mechanism of addition reactions of the carbonyl group and various reagents, such as H-and CN-addition. The chapter deals with the intermediates of the addition-elimination reactions of the carbonyl group, ester hydrolysis, and other addition-eliminations on carboxylic acids and their derivatives. It analyses the transition states, energy profile, stereochemistry, and competition with elimination of the reactions of halogenoalkanes by unimolecular processes.