Hydrohalogenation

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Hydrohalogenation

Reactions involving alkynes


Lecture number:
12
Pages:
1
Type:
Lecture Note
School:
North Carolina State University
Course:
Ch 220 - Introductory Organic Chemistry
Edition:
1

Unformatted text preview:

CH 220 1st Edition Lecture 12 Outline of Current Lecture I. Reactions involving alkynes Current Lecture Alkynes Triple bond must be in the parent chain and get the lowest number Has a linear structure, not cis or trans Addition of HX (Hydrohalogenation)  Addition of HCl or other hydrohalogen  Goes through 2 reactions o 1st equivalent – goes to a double bond (1:1 ratio of alkyne and hydrohalogen) o 2nd equivalent – goes to a single bond (1:2 ratio of alkyne and hydrohalogentation) o How far you take the reaction depends on what the required end product is Halogenation  Addition of Br2 or Cl2  1st equivalent (1:1) results in a double bond with a trans configuration  2nd equivalent (1:2) results in a single bond Hydrogenation  Initially goes to a double bond (Cis configuration)  Then goes to a single bond automatically  For hydrohalogenation and halogenation, you are able to measure out the reactants in order to get a 1:1 or 1:2 reaction, but with hydrogenation, because there is a huge amount of H2 that is required to be pumped into the chamber, it is impossible to measure the reactants. Instead, a catalyst can be used in order to stop the reaction at the double bond, which has huge commercial value. This catalyst is Lindler Pd and it is a proprietary compound catalyst that stops the reaction at the double bond so that it doesn’t go any further. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.



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