Question

Alcohols, Phenols and Ethers
Alcohols and phenols are formed when a hydrogen atom in a hydrocarbon, aliphatic and aromatic respectively, is replaced by -OH group. These classes of compounds find wide applications in industry as well as in day-to-day life. For instance, have you ever noticed that ordinary spirit used for polishing wooden furniture is chiefly a compound containing hydroxyl group, ethanol. The sugar we eat, the cotton used for fabrics, the paper we use for writing, are all made up of compounds containing -OH groups. The common name of an alcohol is derived from the common name of the alkyl group and adding the word alcohol to it. For example, \(\mathrm{CH_3OH}\) is methyl alcohol. The simplest hydroxy derivative of benzene is phenol. It is its common name and also an accepted IUPAC name. As structure of phenol involves a benzene ring, in its substituted compounds the terms ortho (1,2-disubstituted), meta (1,3-disubstituted) and para (1,4-disubstituted) are often used in the common names.
In ethers, the four electron pairs, i.e., the two bond pairs and two lone pairs of electrons on oxygen are arranged approximately in a tetrahedral arrangement. The bond angle is slightly greater than the tetrahedral angle due to the repulsive interaction between the two bulky (-R) groups.

The catalyst involved in the production of methanol through hydrogenation of carbon monoxide is

• A. ZnO-Cr\(_2\)O\(_3\)
• B. ZnO/Pt
• C. Anhyd.AlCl\(_3\)
• D. Anhyd.FeCl\(_3\)

Hint:

Industrial methanol from CO and H2 uses a zinc oxide and chromium oxide catalyst.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Methanol is made industrially from synthesis gas, which is a mixture of CO and H2. The reaction needs a catalyst, high pressure and heat.

Step 2: Key Formula or Approach:
The reaction is \(CO + 2H_2 \to CH_3OH\). The industrial catalyst is a mixed oxide of zinc and chromium, run at 200-300 atm and 573-673 K.

Step 3: Check option (1):
ZnO-Cr2O3 is the standard industrial catalyst for making methanol from CO and H2. So option 1 is CORRECT.

Step 4: Check option (2):
ZnO/Pt is not the catalyst used for this process. Platinum is used in other reactions such as hydrogenation of alkenes. So option 2 is WRONG.

Step 5: Check option (3):
Anhydrous AlCl3 is a Lewis acid used in Friedel-Crafts reactions. It plays no role in making methanol. So option 3 is WRONG.

Step 6: Check option (4):
Anhydrous FeCl3 is also a Lewis acid, used in halogenation of benzene. It is not used for methanol. So option 4 is WRONG.

Final Answer:
Methanol is made from CO and H2 over ZnO-Cr2O3. This is option 1.\[ \boxed{\mathrm{ZnO\text{-}Cr_2O_3}} \]