Research duo develop new green way to synthesize vanillin from sawdust

Jun 19, 2013 by Bob Yirka report
FTIR spectra of the standard vanillin (a) and the oxidation product (b). Credit: arXiv:1306.2442 [physics.chem-ph]

(Phys.org) —Chemical researchers D K Abdullah and Ahmad Shamsuri of University Putra Malaysia have found a way to synthesize vanillin from sawdust in an environmentally friendly way. In their paper they've uploaded to the preprint server arXiv, the two describe how they used an ionic liquid to dissolve lignin found in rubber tree sawdust to produce vanillin.

Vanilla is a flavoring found naturally in some orchids—it's the ingredient that gives fudge its kick. Its popularity has grown over the years to the point where demand now far exceeds the amount that can be extracted from the delicate flower pods. For that reason, manufactures have looked for ways to produce it artificially. A method of using lignin found in sawdust was developed and put into use, but soon fell into disfavor due to . Another method, still in use, was developed based on a petrochemical material called guaiacol, but it's expensive and tied to oil . For that reason, scientists have continued to look for a cheaper, less environmentally hazardous way to use the lignin found in wood products.

In this new effort, the researchers looked to —salts in liquid form. Using them in commercial applications is still relatively new as they are generally quite toxic. Recently, however, developments in chemistry have led to some types that are less reactive and are therefore safer and cleaner to use. Abdullah and Shamsuri thought one of these, 1,3-dimethylimidazolium methylsulphate might be used to help synthesize vanillin.

They started by dissolving lignin in the ionic liquid and then caused oxygen to bubble up through the result. Next, they filtered the liquid separating out the various by-products, one of which was vanillin. To test its purity they performed Fourier transform , and ultraviolet-visible analyses on the liquid and found it to be suitable for use as .

The two conclude that their process could very easily be scaled up to allow for the commercial production of vanillin in a way that is cheaper than those based on petrochemicals and more environmentally friendly than others that use sawdust.

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More information: A Preliminary Study of Oxidation of Lignin from Rubber Wood to Vanillin in Ionic Liquid Medium, arXiv:1306.2442 [physics.chem-ph] arxiv.org/abs/1306.2442

Abstract
In this study, lignin was oxidised to vanillin by means of oxygen in ionic liquid (1,3-dimethylimidazolium methylsulphate) medium. The parameters of the oxidation reaction that have been investigated were the following: concentration of oxygen (5, 10, 15 and 20 ft3 h-1), reaction time (2, 4, 6, 8 and 10 h) and reaction temperature (25, 40, 60, 80 and 100{deg}C). The Fourier transform infrared spectroscopy, high performance liquid chromatography and ultraviolet-visible analyses were used to characterise the product. The results revealed vanillin as the product obtained via the oxidation reaction. The optimum parameters of vanillin production were 20 ft3 h-1 of oxygen for 10 h at 100{deg}C. In conclusion, 1,3-dimethylimidazolium methylsulphate could be used as an oxidation reaction medium for the production of vanillin from rubber wood lignin.

via ArxivBlog

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User comments : 5

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JRi
not rated yet Jun 19, 2013
Quite interesting. However, the paper fails to report any yield percentages they were able to obtain. Only discussion about the purity of the vanillin isolate.
ValeriaT
2 / 5 (1) Jun 19, 2013
ValeriaT
1.3 / 5 (3) Jun 19, 2013

Artificial vanilla is a poor substitute for vanilla flavoring from vanilla beans; it lacks the complexity of other aromatics which, when combined, produce the overall flavor. The artificial versus the natural flavor can be likened to the difference in sound between a single instrument and a symphony orchestra. While they both may play the same notes, the single instrument cannot duplicate the orchestra's tonal richness. Hence, natural vanilla commands a roughly five-fold retail price premium over its artificial challenger.

To produce a reasonable substitute, one must therefore synthesize at least the main five organic compounds constituting vanilla flavor and mix them in their proper proportions.

Shabs42
not rated yet Jun 19, 2013

Artificial vanilla is a poor substitute for vanilla flavoring from vanilla beans; it lacks the complexity of other aromatics which, when combined, produce the overall flavor.


Except that most of those compounds are volatile and burn off at high temperatures. In a batch of cookies the difference is negligible at best. In brownies, you might know the difference if you really know what you're looking for. At the cake level you can probably tell a high quality vanilla from the fake stuff. For raw preparations such as custard; you nailed it. No comparison between the two. That's why I keep a small bottle of the good stuff for low temperature use and use the huge bottle of cheap stuff for cookies and brownies.
ubavontuba
1 / 5 (1) Jun 20, 2013
Anyone ever have a bad batch of artificial vanilla flavoring? I have. I swear the stuff actually tasted like wood. You could have added it to a weak batch of Merlot to get a bolder oak flavor.