Organic Chemisty (very urgent!)

Question

How to convert propan-1-ol to ethane?

I think: propan-1-ol -> 1. (conc H2SO4, heat) propene -->2. (O3, Zn dust/CH3COOH) ethanal+ methanal
ethanal-->3 (NaBH4, methanol) ethanol--> 4 (conc H2SO4, heat) ethene--> 5 (H2, Pt, heat) ethane

But it involves many steps and it gives a mixture of products in step 2, any better method?

Very urgent! Please kindly help me!

Answer 1

I suggest the following synthetic pathway :

(1) CH3CH2CH2OH -(K2Cr2O7/H3O+/heat)→ CH3­CH2COOH

(2) CH3CH2COOH -(NaOH)→ CH3CH2COONa

(3) CH3CH2COONa -(NaOH/fuse)→ CH3CH3

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Firstly, steps (2) and (3) can be combined into one single step practically.

Secondly, the method used in step (3) is known as decarboxylation of sodium carboxylate. This is an old method (out of HKAL syllabus), and is good to prepare methane from sodium ethanoate. In the preparation of ethane from sodium propanoate (as in step (3)), methane is the major by-product.
Reference : Part 4 in the following webpage :
http://72.14.235.104/search?q=cache:7A5Lx1TDQlYJ:portal.kmpp.matrik.edu.my/mod/resource/view.php%3Finpopup%3Dtrue%26id%3D1038+CH3CH2COONa%2BNaOH%2BCH3CH3&hl=zh-TW&ct=clnk&cd=1&gl=hk

Thirdly, the overall synthesis is meaningless. This is because costs of the reactant, reagents and conditions are much more expensive than the cost of ethane.