Author Topic: Malonic acid from cooking oils  (Read 4239 times)

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Malonic acid from cooking oils
« on: May 10, 2004, 06:37:00 AM »
While browsing old chemistry books and the hive, four points caught ning's mind:

1. Malonic acid is rather desired and hard to get.
2. Double bonds can be split to carboxylic acids by KMnO4 or O3
3. Linoleic acid, a constituent of oil, has two double bonds in the right place (carbons 9 and 12, IIRC) to produce malonic acid, and
4. Linoleic acid constitutes > 50% of the fatty acids in soybean oil, and ~ 35% of corn oil.

Let's bee more specific here.

The three oils that have the most linoleic acid are:

Corn oil, 34-42%
Cottonseed oil, 40-48%
Soybean oil, 50-59%

Soybean oil is cheap, so let's imagine we are using this.

Linoleic acid is: CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH
It will split into
-Malonic acid
-Hexanoic (Caproic) acid
-Nonanedioic (Azelaic) acid

Oleic acid is: CH3(CH2)7CH=CH(CH2)7COOH
It will split into
-Nonoic (Pelargonic) acid
-Nonanedioic acid

So our soybean oil if ozonized will have an equation something like this, neglecting glycerin for the moment:


if we pretend that normal soybean oil has 50% linoleic acid (reasonable):

1000 g oil * 50% / 280 = 1.78 moles * 104 = 186 g malonic acid. Not bad.

This would require theoretically 5.4 moles of ozone (2 for linoleic, 1 for oleic), which would weigh 48 grams. Alternately, it would need 2, perhaps 3 equivalents KMnO4 to do the job. That's about 475 g KMnO4.

Perhaps percarbonate or peroxide + some kind of catalyst can cleave alkenes? Like Fe(II)<-->Fe(III) system?

Ning thinks an air-oxidation system would bee ideal for this if there were a cheap & easy catalyst for the job.

Separation of the various components is a sticky issue, but probably would involve solubility differences. Perhaps following the Org syn procedure:

(Malonic Acid)

A solution of 600 g. of anhydrous calcium chloride in 1.8 l. of water warmed to 40° is added slowly with rapid mixing to the hot sodium malonate solution. A cheese-like precipitate of calcium malonate is formed immediately and becomes coarsely crystalline on standing for twenty-four hours. After the supernatant solution is decanted, the calcium malonate is washed by decantation four or five times with 500-cc. portions of cold water. It is then transferred to a filter, sucked as dry as possible, and dried in the air, or at 45–50°, to constant weight. The yield is 800–900 g.
The dry calcium malonate is placed in a 3-l. round-bottomed flask with sufficient (750–1000 cc.) alcohol-free ether (Note 3) to make a paste which can be stirred. The flask is surrounded by an ice bath, and the well-stirred salt is treated with 1 cc. of 12 N hydrochloric acid for each gram of salt. After the acid has been added slowly through a dropping funnel, the solution is transferred to a continuous extractor (Note 4) and extracted with ether until no more malonic acid is obtained. The product, as obtained from the undried ether solution by concentration, filtration, and drying in the air, melts at 130° or higher and is sufficiently pure for most purposes. The yield is 415–440 g. (75–80 per cent of the theoretical amount).

This seems to take advantage of the fact that calcium salt of this dibasic acid is insoluble in water.

Whether this would bee true for the other acids produced is open to question. However, given their size it seems likely they would bee rather lipophilic and easy to remove with repeated nonpolar extractions.

Ning is coming to the strong belief that a home ozone generator is very handy to have around. With one, a bee could have almost unlimited amounts of malonic acid from electricity, air, and cooking oil. And that's just for this synthesis.

Even if one were not in the mood for barbiturates, malonic acid is good for making: Tropane (oooh, cocaine analogs) and cinnamic acids (benzaldehydes--> phenethylamines)

Ning hopes somebee is crazy enough to try this out. Who's the downer bee these days?