Vanillin, Organic spectroscopy

Vanillin, a promising biobased building-block for monomer synthesis

Green Chem., 2014, Advance Article
DOI: 10.1039/C3GC42613K, Paper

Maxence Fache, Emilie Darroman, Vincent Besse, Remi Auvergne, Sylvain Caillol, Bernard Boutevin

Corresponding authors

^a

Institut Charles Gerhardt, UMR CNRS 5253, Equipe Ingénierie et Architectures Macromoléculaires, ENSCM, 8 rue de l'Ecole Normale, 34296 Montpellier, France

^b

COLAS S.A., 7 place René Clair, 92653 Boulogne-Billancourt, France

We report the synthesis of new aromatic biobased building-blocks from vanillin, for their promising use in polymer synthesis.

http://pubs.rsc.org/en/Content/ArticleLanding/2014/GC/C3GC42613K?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Vanillin was used as a renewable building-block to develop a platform of 22 biobased compounds for polymer chemistry. Vanillin-derived biobased monomers bearing epoxy, cyclic carbonates, allyl, amine, alcohol and carboxylic acid moieties were synthesized. They can be used, among many others, in epoxy, polyester, polyurethanes, and Non-Isocyanate PolyUrethanes (NIPU) polymer synthesis. The epoxy-functionalized compounds were synthesized under solvent-free conditions and are original biobased aromatic epoxy monomers. Cyclic carbonates were prepared through a catalytic reaction between epoxy compounds and CO₂. Thiol–ene reactions allowed the functionalization of allylated compounds with amines, acids and alcohols. The amine-functionalized compounds are, to our knowledge, the first non-aliphatic biobased amine hardeners, usable either in epoxy or NIPU materials.

1H (proton) NMR spectrum for 0.037 grams of vanillin in .5 milliliters of CDCl₃ (deuterated trichloromethane) taken at 89.56 MHz showing location correlated peaks.


VANILLIN





13C NMR

This ¹³C spectrum exhibits resonances at the following chemical shifts:

Shift (ppm)
191.6	128.0
152.4	115.0
147.7	109.4
130.0	56.6

Point to a peak to learn more about it. Note: The peak at 130.4 ppm is much smaller than the one at 130.5 ppm. Also, the ¹H spectrum is often helpful.

13C NMR

This ¹³C spectrum exhibits resonances at the following chemical shifts:

Shift (ppm)
191.6	C=O
152.4	CH OF OCH3
147.7	CH OF OH
130.0	CH OF CHO

Point to a peak to learn more about it. Note: The peak at 130.4 ppm is much smaller than the one at 130.5 ppm. Also, the ¹H spectrum is often helpful.

128   CH ON AROM RING PARA TO OH, ORTHO TO CHO

115.0    CH ON AROM RING ORTHO TO OH AND CHO FUNCTIONS

109.4      CH ON AROM RING ORTHO TO OCH3 AND META TO OH
56.0           OCH3



1D DEPT90




2D [1H,13C]-HMBC




2D [1H,13C]-HSQC



2D [1H,1H]-COSY

Chemical synthesis

The demand for vanilla flavoring has long exceeded the supply of vanilla beans. As of 2001, the annual demand for vanillin was 12,000 tons, but only 1,800 tons of natural vanillin were produced. The remainder was produced by chemical synthesis. Vanillin was first synthesized from eugenol (found in oil of clove) in 1874–75, less than 20 years after it was first identified and isolated. Vanillin was commercially produced from eugenol until the 1920s. Later it was synthesized from lignin-containing "brown liquor", a byproduct of the sulfite process for making wood pulp.^[9] Counter-intuitively, even though it uses waste materials, the lignin process is no longer popular because of environmental concerns, and today most vanillin is produced from the petrochemical raw material guaiacol. Several routes exist for synthesizing vanillin from guaiacol.

At present, the most significant of these is the two-step process practiced by Rhodia since the 1970s, in which guaiacol (1) reacts with glyoxylic acidby electrophilic aromatic substitution. The resulting vanillylmandelic acid (2) is then converted via 4-Hydroxy-3-methoxyphenylglyoxylic acid (3) to vanillin (4) by oxidative decarboxylation.^[4]