Production benzaldehyde

Natural" benzaldehyde can be produced in a number of ways. The FDA regulations regarding natural products are found in 21 CFR 101.22. At the present time there is a controversy over what the term natural really means with regard to benzaldehyde. Whether a particular benzaldehyde product is natural or not becomes an issue only if the final product is said to contain natural flavors. 

There are at least two routes currently being used to produce natural benzaldehyde. Principal flavor houses are reported to market a product which is derived from cassia oil. The chief constituent of cassia oil is cinnamic aldehyde which is hydrolyzed into its benzaldehyde and acetaldehyde constituents. This is a fermentative retroaldol reaction. Whether this hydrolysis allows the final benzaldehyde product to be considered natural is of great concern. The FDA has reportedly issued an opinion letter that benzaldehyde produced from cassia oil is not natural (15). 

The other significant production method for natural benzaldehyde involves the steam distillation of bitter almond oil which has been derived from the kernels of fmit such as apricots, peaches, cherries, plums, or pmnes. The benzaldehyde product obtained in this fashion is claimed to have a superior flavor profile. The use of peach and apricot pits to produce the more profitable product laettile apparently affects the supply available to natural benzaldehyde producers. 

The subject of natural benzaldehyde came to the forefront in 1984 when it was found that a natural benzaldehyde product, labeled "oil of benzaldehyde," was actually made synthetically by the air oxidation of toluene followed by careful fractionation to remove trace impurities. This finding was accomphshed by the Center for AppHed Isotopic Studies, University of Georgia, and involved measuring the amounts of and in that material. 

Benzaldehyde, Product Information Bulletin, Kalama Chemical Corp., Kalama, Wash., Jan. 1,1989. 

Role of the p-Hydroxyl Group. Preliminary nitrobenzene oxidation experiments were conducted on several benzylic hydroxyl compounds, both with and without a p-hydroxyl group (5). Contrary to what was expected from the literature, some compounds without a p-hydroxyl group formed benzaldehyde products. 

Group 1 Relatively high benzaldehyde production and relatively low combustion oxides of tantalum, tungsten, zirconium and molybdenum. 

Group 2 Relatively high benzaldehyde production and relatively high combustion oxides of manganese, chromium, copper, nickel, thorium and uranium. 

Deuterium site-specific distribution stores infonnation about the history of a benzaldehyde product. Products from the same source should have similar isotope distribution. Therefore, comparing a test sample s deuterium site-specific distribution with that of standard samples can identify the origin of the test sample. The precondition for a successful identification is that tlie... 

While the deuterium spectra of benzaldehydes from different sources do not appear (upon visual inspection) to have significant differences from one another, other than some variation in intensity, the deuterium distribution of benzaldehyde does form clusters on a principal component analysis plot. Benzaldehyde products from the same source have similar deuterium distributions and are therefore close to each otlier on the plot (Figure 1). Thus, the origin of benzaldehyde can be differentiated based on site-specific deuterium distribution. Products outside of the clusters of knoivn samples are normally considered as originating from an unknown source or as a mixture of benzaldehyde from different known sources. 

Because the deuterium distribution on the aromatic sites reserves the original state of the starting material, while the carbonyl deuterium is labile during the production, only the aromatic deuterimn abundance should be used as the primary data for the discrimination analysis of benzaldehyde products. 

SNIF-NMR is a powerful method for the authentication analysis of benzaldehyde products. However, manufacturing processes may cause the deuterium to shift on the carbonyl site. In some cases, the current SNIF NMR method cannot differentiate abnormal distribution of deuterium caused by adulteration or by production processes that lead to false negative or false positive conclusions of a product. Deuterium on the aromatic sites of benzaldehyde is more stable and is not affected by the known manufacturing processes. The aromatic deuterium distribution is very specific and can be used to classify benzaldehyde products from fossil or different botanical origins. The proposed improvement needs to be further developed and validated. 

Startg. m. allowed to react 1 hr. at -78° with -butyllithium in tetrahydrofuran, then treated with benzaldehyde -> product. Y 86%. F. e., also with ketones, s. A. Anciaux et al., Tetrah. Let. 1975, 1617 prepn. of selenothioacetals and related compds. cf. ibid. 1975, 1613. 

For example, benzylamine forms benzaldehyde products , and diethylamine is oxidised to a mixture of acetic acid, ammonia, ethanol and acetohydroxamic acid . 

At the end of 2004, phenol production at DSM stopped. The operating process of the existing toluene oxidation plant changed dramatically, producing much less benzoic acid but maintaining the same level of benzaldehyde production. 

Other substrates have also been suggested for benzaldehyde production, which are always coupled with product removal strategies. However, obtaining them from natural sources might be problematic. 

Tri- er -butylphenylmagnesium bromide prepared from 2,4fi-tn-tert-hutyl-bromobenzene and Mg in tetrahydrofuran treated under dry Ng with at least 3 equivalents benzaldehyde -> product. Y 55%. F. e. and limitations s. A. Rieker, Y. Butsugan, and M. Shimizu, Tetrah. Let. 1971, 1905. 

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