Show how you could prepare 1-butyne from 1-chloro butane
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1-Chlorobutane is a primary alkyl halide, and primary alkyl halides naturally prefer SN2 reactions, but we need to do an E2 to get 1-butene.
There are two ways that you can increase the amount of elimination, so that 1-butene becomes the major product.
1. Elimination is favored by using "bulky" bases. If the base is too big, it can't reach the carbon atom to do SN2. It is much easier for a "bulky" base to remove a hydrogen, giving an E2 reaction. In the image I've attached, I've used the "bulky" base t-butoxide. This is probably the most common base for this type of problem, although your chemistry professor may have shown you other "bulky" bases you could use for the same thing, like LDA.
2. Heating up a reaction makes it favor elimination over substitution, for entropic reasons.
Your professor may prefer you to use both of these at the same time, or he/she may prefer one over the other, but they both work to make 1-butene the major product.
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