Vanillin 4-

Next to furfural, vanillin is one of the most important aromatic compounds based on renewable raw materials. Current world production of vanillin is around 8,000 tpa. 

There are three industrially proven methods for recovering vanillin, the first two being based on renewable raw materials. 

Extraction from the waste sulfite lye from pulp production. 

Oxidation of isoeugenol, which is itself obtainable from clove oil. 

Synthetic production from guaiacol and glyoxylic acid. 

Montezuma II (about 1466-1520) drank Xocolatl, [134] a chocolate drink made from cocoa, before he paid coiut to his wives, and Giacomo Girolamo Casanova (1725-1798) was convinced that chocolate possesses aphrodisiac properties. The Aztecs used vanilla to enhance the aroma of chocolate, centuries before in 1520 the Spanish Conquistador Hernan Cortes (1485-1547) tasted it at the court of Montezuma (Fig. 3.31). 

Because of its taste, its aroma and its texture, eating chocolate is a hedonistic experience for many people, one, which cheers them up. Scientifically it can be shown, that the flavonoids in cocoa are powerful antioxidants, which serve to protect against age-related diseases, e.g. of the heart, and also against cancer. 

Up to now, most efforts have been devoted to the investigation of bioconversion processes rather than of de novo procedures, because they offer more economic advantages. Specific inexpensive, readily available, and renewable natural substrates are added to the fermentation medium so that they can be converted into the desirable flavor compound(s). In contrast to de novo synthesis, yields are high enough to permit the industrial exploitation of the bioproduction process. 

Problems may arise from the poor water solubUity of the starting substrate, or from the inhibition of cell growth due to either the substrate or the product over a certain threshold concentration. Methods for the continuous addition of substrate at non-harmful concentrations and removal of the product(s) have been developed. Among these, the most effective ones are the pervaporation method [30], or the addition to the culture media of a nonsoluble solid or nonmiscible hydrophobic liquid phase to create a two-phase system in which the desired volatile is sequestered by the solid or the hydrophobic hquid phase. 

For the reasons outlined above, as a general consideration, the research in the field of the biotechnological production of flavors has been very productive therefore, a comprehensive review would be inappropriate and out of scope. 

In the following, we will focus our attention on the flavor ingredients with the highest production volume (listed in Table 9.1), reporting specifically on practically useful processes that afford industrially interesting yields. 

Vanillin (4-hydroxy-3-methoxybenzaldehyde) is the most important flavor ingredient available on the market. Natural vanillin is extracted from the beans, or pods, of the orchid Vanilla planifolia, V. tahitiensis, and V fragrans, mainly cultivated in Madagascar, Mexico, Tahiti, and Indonesia. Natural vanilla flavor supplies cover 1% of the demand the remainder is synthesized cheaply by chemical routes. Vanillin is employed not only in the F F industry, but it is also a key intermediate in the production of chemicals and pharmaceuticals (e.g., drugs, herbicides, antimicrobial agents, antifoaming agents) [31]. 

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Guaiacol has a very characteristic odour and burning taste its medicinal properties are identical with those of creosote. Used in the preparation of vanillin and paparvarin and for denaturing alcohol. 

CgHeOa. White crystals m.p. 37°C, b.p. 263°C. Occurs associated with vanillin. Obtained on oxidation of various natural products such as piperine. Used extensively in soap perfumery. 

CaH803. Fine white needles, m.p. 82°C, b.p. 285°C, strong vanilla odour, characteristic taste. It occurs extensively in nature, and is the odoriferous principle of the vanilla pod it can be obtained from the glucoside coniferin. Vanillin is made commercially from the ligno-sulphonic acid obtained as a by-product in the manufacture of wood pulp. It is one of the most important flavouring and perfuming... 

CgHjoO,. A compound of largely historical interest for its role in establishing the structure of many natural products. Methylation of vanillin gives veratraldehyde which may be oxidized to veratric acid. Veratric acid was identified as a degradation product of the alkaloid papaverine. 

Substances suitable for the estimation acetanilide, sucrose, glucose, cinnamic acid, diphenyl amine, salicylic acid, vanillin, />"bromoacetanilide, toluene p-sul phonamide. 

The readily-available vanillin is employed in the starting material in this preparation. 

VANILLIN In vanilla beans of course. But never more than 2%. This stuff is bought as a synthetic and is cheap and legal. 

To a stirred, cooled (0°C) solution of I52.15g (1.0 mol) of vanillin in 1000ml of methanol was added during 20 min 176.Og (1.1 mol) of bromine at such a rate that the temperature was kept below 20°C. The mixture was stirred at room temperature for lh, cooled to 0°C, and treated during 30 min with 500 ml of cold (5°C) water. Stirring was continued for 15 min and the product was collected by filtration. It was washed with water (4x500 ml), then with 500 ml of... 

To vanillin (15.2g, 0.1 mol) in glacial acetic acid (75 ml) is added bromine (17.6g, 0.11 mol). After stirring for 1h, the reaction mixture is diluted with ice/water (200ml), the precipitated solid is filtered, washed with water, and dried to give 5-bromovanillin, yield 22. Og (95%)... 

This is a nifty little way to turn catechol or guaiacol into protocate-chualdehyde or vanillin using what is called the Riemer-Tiemann reaction [137 p824, 138], It is a really ancient reaction and only works on benzene molecules that have an OH group. One needs to use KOH instead of NaOH because it is better at promoting para substitutions (don t ask). And if one is going to make vanillin from guaiacol then there needs to be a little ethanol in the reaction as well. 

When making vanillin from guaiacol the chemist can smell success because the product will have an intense vanilla odor. One can even flavor cookies with the stuff (true ). This Riemer-Tiemann method is also an excellent way to get salicylal-dehyde from phenol in yields of up to 50%. The chemist does everything the same except uses NaOH instead of KOH. 

Most of the thiazoles studied absorb in the ultraviolet above 254 nm, and the best detection for these compounds is an ultraviolet lamp (with plates containing a fluorescent indicator). Other indicator systems also exist, among which 5% phosphomolybdic acid in ethanol, diazotized sulfanilic acid or Pauly s reagent (Dragendorff s reagent for arylthiazoles), sulfuric anisaldehyde, and vanillin sulfuric acid followed by Dragendorff s reagent develop alkylthiazoles. Iodine vapor is also a useful wide-spectrum indicator. 

These trivial names may be retained citral (3,7-dimethyl-2,6-octadienal), vanillin (4-hydroxy-3-methoxybenzaldehyde), and piperonal (3,4-methylenedioxybenzaldehyde). 

Gunzherg s reagent (detection of HCl in gastric juice) dissolve 4 g of phloroglucinol and 2 g of vanillin in 100 mL of absolute alcohol use only a freshly prepared solution. 

COLORANTSFORFOOD,DRUGS,COSTffiTICSANDTffiDICALDEVICES] (Void) -vanillin in [VANILLIN] (Vol 24)... 

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