Question

Approximately 1 million tonnes of ethanol are produced industrially every year.

Compare its two methods of synthesis: 1) Natural fermentation vs 2) Petrochemical synthesis. What are the advantages/inconveniences of each procedure?

Answer 1

Answer: Approximately 1 million tonnes of ethanol are produced industrially every year.

We compare as follows its two methods of synthesis: 1) Natural fermentation vs 2) Petrochemical synthesis.

(1) Natural fermentation   

(i) Ethanol can be prepared by the fermentation of molasses. Molasses is the mother liquor left after the crystallization of sugarcane juice. During this period, enzymes sucrase and zymase which are present in yeast, convert sugar into ethanol.

(ii) The raw material used in the process is renewable i.e. molasses from sugarcane juice.

(iii) The process operates as batch process.

(iv) It requires lot of labour and work during the process.

(v) The rate of reaction during the process is slow.

(vi) It requires normal temperature and pressure condition such as 30 0C and 1 atm pressure.

(vii) The product formed during the process is impure and for purification of product needs further treatment.

(viii) It requires very little energy during the process.

Vs

(2) Petrochemical synthesis

(i) Ethanol can be prepared in the petrochemical industry via direct and indirect hydration of ethylene. Catalytic direct ethylene hydration produces ethanol by a reversible exothermic reaction between ethylene and water vapor.

(ii) The raw material used in the process is nonrenewable i.e. ethylene obtained from crude oil.

(iii) The process operates as continuous process.

(iv) It requires less labour and work during the process.

(v) The rate of reaction during the process is fast.

(vi) It requires high temperature and pressure conditions during the process i.e. 300 0C and 60-70 atm.

(vii) The product formed during the process is pure and no by products is made during the process.

(viii) it requires lot of energy during the process.

The advantages and inconveniences of each procedure is summarized as follows:

(1) Natural fermentation process

Advantages:

(i) The raw material used in the process is renewable i.e. molasses from sugarcane juice.

(ii) The process operates as batch process.

(iii) It requires normal temperature and pressure condition such as 30 0C and 1 atm pressure.

(iv) It requires very little energy during the process.

Inconveniences:

(i) It requires lot of labour and work during the process.

(ii) The rate of reaction during the process is slow.

(iii) The product formed during the process is impure and for purification of product needs further treatment.

(2) Petrochemical synthesis:

Advantages:

(i) It requires less labour and work during the process.

(ii) The rate of reaction during the process is fast.

(iii) The product formed during the process is pure and no by products is made during the process.

Inconveniences:

(i) The raw material used in the process is nonrenewable i.e. ethylene obtained from crude oil.

(ii) It requires high temperature and pressure conditions during the process i.e. 300 0C and 60-70 atm.

(iii) it requires lot of energy during the process.

(iv) The process operates as continuous process.