I have been working on making benzene starting with benzoic acid form salicylic acid. First I added magnesium powder to a solution of salicylic acid in isopropyl. I was hopping that the Mg would reduce it and make benzoic acid and it would precipitate. Instead the Mg dissolved and over time the solution turned black. What happened, did the benzoic acid dissolve, did it forum magnesium benzoate or salysilate?

I'm not sure why you thought it would do that. Did you notice any bubbling?

Yes a little

And the vessel probably warmed up a little? Most likely what you did was make a Mg salt - I suspect of the acid - and hydrogen gas. You were never going to get rid of the phenolic OH like that. What is this for, exactly?

were you attempting a grignard reaction. You'd need ether, not propanol, and an alkylide

That wouldn't work either. What do you think would happen if you had a Grignard reagent in the presence of a carboxylic acid?

well how should I remove the OH group and replace it with a H.

I can think of a couple of ways off the top of my head, but they would also mess with your acid group. In any event, your lacking knowledge of organic chemistry is a little concerning and I'm not sure I feel comfortable encouraging you to experiment like this. Maybe try to stick with some simple reactions if you're just doing this for fun and try to get a better feel for the theory before you continue with more complex / dangerous set ups.

That wouldn't work either. What do you think would happen if you had a Grignard reagent in the presence of a carboxylic acid?

exactly why I said he'd need an alkylide

exactly why I said he'd need an alkylide

What? The OP is trying to reduce the phenolic OH of salicylic acid. An alkylhalide (which I assume is what you meant by alkylide) isn't going to help one bit and in fact that was my point. You're suggesting the OP make a Grignard reagent, which is not only very tricky to do effectively, it also won't do what the OP wants. This is why I asked you to consider what a Grignard reagent plus a carboxylic acid would produce.

 

I'm sure I mentioned this to you before in another thread, but it apparently needs repeating; you shouldn't be giving out chemical advice if you don't know what you're talking about.