Question

Describe the following conversions: (i) ethene to acetic acid (ii) acetylene to acetaldehyde (iii) methane to formic acid

Short answer

Question: List the conversions of the three molecules provided, and describe the specific reactions involved in each conversion. Answer: The three conversions are: 1. Ethene to Acetic acid: This conversion involves the oxidation of ethene to ethylene oxide, hydrolysis of ethylene oxide to ethylene glycol, and oxidation of ethylene glycol to acetic acid. 2. Acetylene to Acetaldehyde: This conversion involves the hydrogenation of acetylene to ethene, hydration of ethene to ethanol, and oxidation of ethanol to acetaldehyde. 3. Methane to Formic acid: This conversion involves the oxidation of methane to methanol, oxidation of methanol to formaldehyde, and partial oxidation of formaldehyde to formic acid.

Step-by-step solution

For each conversion: (i) Ethene (C₂H₄) has a structure with a double bond between the two carbon atoms and single bonds to the hydrogen atoms (H). Acetic acid (CH₃COOH) consists of a carboxylic acid group (COOH) attached to a methyl group (CH₃). (ii) Acetylene (C₂H₂) consists of a triple bond between the two carbon atoms and single bonds to the hydrogen atoms (H). Acetaldehyde (CH₃CHO) contains a carbonyl group (C=O) attached to a methyl group (CH₃). (iii) Methane (CH₄) has a structure with a single carbon atom bonded to four hydrogen atoms. Formic acid (HCOOH) consists of a carboxylic acid group (COOH) attached to a hydrogen atom (H). #Step 2: Ethene to Acetic acid conversion process#

The conversion of ethene to acetic acid has the following steps: 1. Oxidation of ethene to ethylene oxide: Ethene is oxidized in the presence of an epoxidation catalyst, such as silver oxide, to form ethylene oxide. C₂H₄ + 1/2 O₂ → C₂H₄O 2. Hydrolysis of ethylene oxide to ethylene glycol: Ethylene oxide reacts with water in the presence of an acidic catalyst to form ethylene glycol. C₂H₄O + H₂O → HOCH₂CH₂OH 3. Oxidation of ethylene glycol to acetic acid: Ethylene glycol is oxidized in the presence of an oxidizing agent, commonly KMnO₄, to form acetic acid. HOCH₂CH₂OH + 2 [O] → CH₃COOH + H₂O #Step 3: Acetylene to Acetaldehyde conversion process#

The conversion of acetylene to acetaldehyde involves the following steps: 1. Hydrogenation of acetylene to ethene: Acetylene is partially hydrogenated in the presence of the Lindlar catalyst to produce ethene. C₂H₂ + H₂ → C₂H₄ 2. Hydration of ethene to ethanol: Ethene reacts with water in the presence of a catalytic amount of acid to yield ethanol. C₂H₄ + H₂O → CH₃CH₂OH 3. Oxidation of ethanol to acetaldehyde: Ethanol is dehydrogenated or oxidized in the presence of an oxidizing agent, often PCC, to produce acetaldehyde. CH₃CH₂OH + [O] → CH₃CHO + H₂O #Step 4: Methane to Formic acid conversion process#

The conversion of methane to formic acid involves the following steps: 1. Oxidation of methane to methanol: Methane is partially oxidized in the presence of an oxygen source and a metal oxide catalyst, such as MoO₃, V₂O₅, or Cr₂O₃, to produce methanol. CH₄ + 1/2 O₂ → CH₃OH 2. Oxidation of methanol to formaldehyde: Methanol is further oxidized in the presence of an oxidizing agent, often silver or copper catalysts, to form formaldehyde. CH₃OH + 1/2 O₂ → HCHO + H₂O 3. Partial oxidation of formaldehyde to formic acid: Formaldehyde is partially oxidized by an oxidizing agent to form formic acid. HCHO + 1/2 O₂ → HCOOH