Quinoline help

[saaz55]

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i'm reading that H2/BaSO4 is catalyzed with Lindlar's catalyst and quinoline so that the hydrogenation stops at the formation of an alkene. Now if the quinoline wasn't there it would have hydrogenated to an alkane. On the exam, do we assume that quinoline is/is not there or do we have to see if they write it down on the reaction of the question. thanks for your help

 

[TimeforDAT]

if quinoline is used, it will specifically say it. if you don't see quinoline there, then you assume its not there and will and the final product would be an alkane.

 

[Flipper405]

I have to disagree; quinoline is part of the Lindlar catalyst. The purpose of the Lindlar catalyst is to stop the hydrogenation at the alkene.

 

[sacjumpman]

I have to disagree; quinoline is part of the Lindlar catalyst. The purpose of the Lindlar catalyst is to stop the hydrogenation at the alkene.

I agree...

 

[TimeforDAT]

I have to disagree; quinoline is part of the Lindlar catalyst. The purpose of the Lindlar catalyst is to stop the hydrogenation at the alkene.

i'm confused...are you referring to what i said? I believe i made it clear that if no quinoline is used, then the product would be an alkane.

 

[Flipper405]

i'm confused...are you referring to what i said? I believe i made it clear that if no quinoline is used, then the product would be an alkane.

Yes, I'm referring to what you said. I agree that if no quinoline is used, then the product would be an alkane, but without quinoline, it's not the Lindlar catalyst. I believe you assume quinoline is present unless otherwise stated.


*edit* I did a little more snooping around; this seems to be the procedure for preparing the catalyst with other notes:
http://www.orgsyn.org/orgsyn/pdfs/CV5P0880.pdf

The lead additives are also vital to the poisoning of the palladium. However, the notes do say there are alternatives to quinoline available, so I was wrong that saying that quinoline is essential.

However, I still think that you assume quinoline (or an alternative poison) is present unless stated because this is essential to the functioning of the catalyst.

 

[TimeforDAT]

Yes, I'm referring to what you said. I agree that if no quinoline is used, then the product would be an alkane, but without quinoline, it's not the Lindlar catalyst. I believe you assume quinoline is present unless otherwise stated.


*edit* I did a little more snooping around; this seems to be the procedure for preparing the catalyst with other notes:
http://www.orgsyn.org/orgsyn/pdfs/CV5P0880.pdf

The lead additives are also vital to the poisoning of the palladium. However, the notes do say there are alternatives to quinoline available, so I was wrong that saying that quinoline is essential.

However, I still think that you assume quinoline (or an alternative poison) is present unless stated because this is essential to the functioning of the catalyst.

i am NOT assuming quinoline is present. I said in my earlier post that quinoline must be explicitly stated in the reaction, otherwise you don't assume the presence of quinoline.

 

[Flipper405]

i am NOT assuming quinoline is present. I said in my earlier post that quinoline must be explicitly stated in the reaction, otherwise you don't assume the presence of quinoline.

ok

I still say DO assume quinoline is present. whatever.

 

[saaz55]

ok

I still say DO assume quinoline is present. whatever.

lol ok sounds good. thanks for the help people