Isopropyl esters

Hi wcfloyd,

There are several ways to do this. A quick reaction, requiring no catalyst and little heat may be done by reacting an acyl halide (Benzoyl chloride) with an alcohol (Isopropanol). The most common and probably the cheapest is to react a carboxylic acid (benzoic acid) with an alcohol (isopropanol). However, this is a slower reaction and will probably require the use of a catalyst.

I was going to suggest a two-step production scheme:

Step 1) Benzoyl chloride from benzoic acid and either phosphorus pentoxide or thionyl chloride:

Step 2) Reacting the resultant benzoyl chloride with the isopropanol:

However, since you are limited to a SS vessel, the use of chlorides is out.

The best you can do in this case is to react benzoic acid with isopropanol using heat and an acid catalyst:

Even though benzoic acid will dissolve in isopropanol, you will probably be better off to run as a diluted system - solvent:reactants at a 1:1 or 2:1 ratio. My first choice would be chloroform with diethyl ether a close second.

I don't have an idea what your exact process conditions should be, but you can search publications such as the Journal of Organic Chemistry. You will most likely be charged for such an aritcle if you download it online. Alternatively, you can see the article in volumes at a university library - a university that has a strong chemistry program.

Good luck

Mike

Y'know, while I do like providing answers, I ALSO like getting feedback - whether it helped or not.

Thanks for your info. With stainless equipment, we need to stay away from chlorides. We are considering the IPA/benzoic acid route, but waiting on costs of raw materials. also considering propylene with some pressure and an acid catalyst. Looking at processes and costs right now. Haven't loaded the first flask yet.

You don't mention your starting point. Fischer esterification won't work too well with the acid and the secondary alcohol, I wouldn't think.

Perhaps you could use alcoholysis of methyl benzoate, using sodium methoxide as catalyst and excess isopropyl alcohol. Removal of the methanol with a refluxing column might help the position of the equilibrium. Keeping it all dry.

You might have to make the methyl benzoate first, but that should be a simpler task than making the isopropyl ester straight up.

Just some thoughts.

Hi! Could you explain and show the reaction for the alcoholysis you mentioned?

In case you need software to do this, there is freeware to do this:

http://www.acdlabs.com/download/

With this program, you can draw the reactions, then convert them to .gif files that you can upload to this forum using the button.

Mike

Hi,

By chance, I tried that download the other day and it didn't work for me. Tried it again just then and it didn't work again.

Alcoholysis is another term for ester interchange or transesterification. Same reaction as used for making biodiesel.

Still waiting on registration here :(

We haven't picked a starting point yet. I'm still waiting for raw material costs from somebody else on the team. It doesn't seem to be their top priority, for some reason. We are limited to stainless reactors, so any route using chlorides is out. Reactors can handle up to 50 PSI, so benzoic acid and propylene might be of interest if anybody knows of a procedure. They don't have a good distillation column so separating methanol and IPA might not work too well.I appreciate the thoughts guys!