Comments on: Hydrohalogenation of Alkynes

By: James Ashenhurst

James Ashenhurst — Mon, 26 Feb 2024 16:39:44 +0000

In reply to CHANDRU. It is due to the electron-withdrawing nature of the halogens.

By: CHANDRU

CHANDRU — Mon, 26 Feb 2024 16:28:04 +0000

why halo alkenes are less reactive towards addition than corresponding alkenes ? is it some what regarding to the electron withdrawing effect of the halogen on the pi bond deecreasing its electron density ? similar to deactivating nature of halogen in aromatic rings ?

By: James Ashenhurst

James Ashenhurst — Sun, 10 Dec 2023 13:33:33 +0000

In reply to Caroline Lyu. Well, if the internal alkyne isn't symmetrical, then there would be two constitutional isomers (alkenes). Each of those constitutional isomers would be present as a mixture of stereoisomers (E/Z) since these reactions are not very stereoselective. So four, at least.

By: Caroline Lyu

Caroline Lyu — Mon, 20 Nov 2023 23:46:47 +0000

Hello,

What would the reaction look like for an internal alkyne, where there is equal substitution if the alkyne? How many constitutional isomers and products would be formed?

By: James Ashenhurst

James Ashenhurst — Mon, 14 Nov 2022 17:31:34 +0000

In reply to Stanley. The reaction uses stoichiometric (not catalytic) acid.

By: Sabiu bawa

Sabiu bawa — Wed, 12 Oct 2022 12:57:24 +0000

I have. Apriciation of this side. Alot

By: Stanley

Stanley — Mon, 09 Aug 2021 11:52:31 +0000

What catalyst is best for the hydrohalogenation process??

By: Rohan Chowdhury

Rohan Chowdhury — Mon, 26 Apr 2021 07:11:02 +0000

Can rearrangement take place in Hydrohalgenation of Alkynes like it happens in Alkenes.

By: James Ashenhurst

James Ashenhurst — Tue, 02 Feb 2021 19:24:11 +0000

In reply to Mal. Alkenes will be more reactive toward HBr than alkynes. A molecule with both an alkene and an alkyne will react with HBr at the alkene. When an alkene is protonated, the resulting carbocation is sp2 hybridized (33% s character) . When an alkyne is protonated the resulting carbocation is sp hybridized (50% s character). The more s-character present in a carbocation, the harder it is to form (less stable) since the empty orbital will be closer to the nucleus.

By: Mal

Mal — Tue, 02 Feb 2021 07:38:53 +0000

I have questions. What happen if a molecule contain both double bond and triple bond? Do both will be reacted with HBr? And how if only 1 mol of HBr is used? I really confused because i thought maybe one of them will react since only one HBr molecule will react for one reactant molecule.