Question

Give an example reaction that would yield the following products. Name the organic reactant and product in each reaction. a. alkane b. monohalogenated alkane c. dihalogenated alkane d. tetrahalogenated alkane e. monohalogenated benzene f. alkene

Short answer

a. Alkane: A reaction between methane (CH4) and chlorine (Cl2) produces methyl chloride (CH3Cl), a monohalogenated alkane. b. Monohalogenated Alkane: A reaction between ethane (C2H6) and chlorine (Cl2) produces chloroethane (C2H5Cl), a monohalogenated alkane. c. Dihalogenated Alkane: A reaction between chloroethane (C2H5Cl) and chlorine (Cl2) produces 1,1-dichloroethane (C2H4Cl2), a dihalogenated alkane. d. Tetrahalogenated Alkane: A reaction between methane (CH4) and chlorine (Cl2) produces carbon tetrachloride (CCl4), a tetrahalogenated alkane. e. Monohalogenated Benzene: A reaction between benzene (C6H6) and chlorine (Cl2) with a Lewis acid catalyst (AlCl3) produces chlorobenzene (C6H5Cl), a monohalogenated benzene. f. Alkene: A catalytic dehydrogenation reaction between ethane (C2H6) with a platinum catalyst at high temperatures produces ethylene (C2H4), an alkene.

Step-by-step solution

Radical Halogenation of Alkane

An alkane can be synthesized from methane (CH4) via a radical halogenation reaction using chlorine (Cl2) in the presence of light or heat. The reaction can be represented as follows: \(CH_4 + Cl_2 \rightarrow CH_3Cl + HCl\) The reactant in this chemical reaction is methane (CH4) and the main product is methyl chloride (CH3Cl), a monohalogenated alkane. b. Monohalogenated Alkane

Radical Halogenation of Alkane

A monohalogenated alkane can be obtained through the radical halogenation of a higher order alkane. For instance, in this example we will consider the radical halogenation of ethane (C2H6) in the presence of chlorine (Cl2) and light or heat, represented as follows: \(C_2H_6 + Cl_2 \rightarrow C_2H_5Cl + HCl\) The reactant is ethane (C2H6) and the product is monohalogenated alkane, chloroethane (C2H5Cl). c. Dihalogenated Alkane

Dihalogenation of Monohalogenated Alkane

Starting with the monohalogenated alkane from the previous step, we can obtain a dihalogenated alkane by performing another radical halogenation. In this example, we will use chloroethane (C2H5Cl) as our starting monohalogenated alkane and react it with chlorine (Cl2) in the presence of light or heat: \(C_2H_5Cl + Cl_2 \rightarrow C_2H_4Cl_2 + HCl\) The reactant is chloroethane (C2H5Cl) and the product is dihalogenated alkane, 1,1-dichloroethane (C2H4Cl2). d. Tetrahalogenated Alkane

Formation of Tetrahalogenated Alkane

A tetrahalogenated alkane can be prepared by extensive halogenation. In this example, tetrachloromethane or carbon tetrachloride (CCl4) is formed by reacting methane (CH4) with chlorine (Cl2) in the presence of light or heat: \(CH_4 + 4Cl_2 \rightarrow CCl_4 + 4HCl\) The reactant is methane (CH4) and the product is tetrahalogenated alkane, carbon tetrachloride (CCl4). e. Monohalogenated Benzene

Electrophilic Aromatic Substitution

Monohalogenated benzene can be prepared via electrophilic aromatic substitution. In this case, we will add chlorine (Cl2) to the benzene ring with the help of a Lewis acid catalyst, such as aluminum chloride (AlCl3): \(C_6H_6 + Cl_2+ AlCl_3 \rightarrow C_6H_5Cl + HCl+ AlCl_3\) The reactant is benzene (C6H6) and the product is monohalogenated benzene, chlorobenzene (C6H5Cl). f. Alkene

Catalytic Dehydrogenation

Finally, to synthesize an alkene, we can use catalytic dehydrogenation of an alkane. We can take ethane (C2H6) and perform catalytic dehydrogenation using a platinum catalyst at high temperatures: \(C_2H_6 \rightarrow C_2H_4 + H_2\) The reactant in this example is ethane (C2H6) and the product is the alkene, ethylene (C2H4).