Question

ethanol can be produced from ethene then why is it manufactured from molasses or starch​

Answer 1

Answer:

ANSWER :)

Explanation:

Ethanol production process from starch-containing cereals takes place in five steps:

1. Milling - which involves mechanical crushing of the cereal grains to release the starch components.

2. Heating - While adding water and enzymes for conversion into fermentable sugar.

3. Fermentation - The mash is fermented using yeast, whereby the sugar is converted into bioethanol and CO2.

4. Distillation and rectification -Concentration and cleaning the ethanol produced by distillation.

5. Drying - Where dehydration of the bioethanol takes place.

Bioethanol can also be produced directly from sugar syrups. This skips steps 1 and 2, which serve to prepare the grain for the

Answer 2

Molasses is a dark-colored syrupy liquid left over from the crystallization of sugar from concentrated sugar cane juice. Molasses still contains about 30% sucrose, which cannot be separated by crystallization. It is converted to ethanol by the following steps:

(i) Dilution

The molasses is first diluted with water to reduce the sugar concentration to about 8 to 10 percent.

(ii) Addition of ammonium salts

Molasses usually contains enough nitrogenous substances to act as food for the yeast during fermentation. If the nitrogen content of molasses is low, it can be enriched by adding ammonium sulfate or ammonium phosphate.

(iii) Addition of yeast

The solution from step (ii) is collected in large "fermentation tanks" and yeast is added to it. The mixture is kept at a temperature of about 303 K for several days. During this period, the enzymes invertase and zymase present in the yeast cause the sucrose to be converted into ethanol. The fermented liquid is technically called wash.

(iv) Distillation of the washing solution

The main fraction collected is an aqueous ethanol solution, which contains 95.5% ethanol and 4.5% water. This is called a reformed spirit. Distillation of this mixture yields pure alcohol (100%). This is called absolute alcohol.

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