Aldehydes industrial production

Urea—Other Aldehyde Reaction Products. Urea can also react with other aldehydes to form slow release nitrogen fertilizers. However, cost constraints associated with higher aldehydes have either precluded or limited broad commercial development of these products. Two exceptions are isobutyhdene diurea (IBDU), registered trademark of Vigoro Industries, and crotonyHdene diurea (CDU), registered trademark of Chisso-Asahi Fertilizer Co. 

The hydroformylation reaction ( oxo reaction ) of alkenes with hydrogen and carbon monoxide is established as an important industrial tool for the production of aldehydes ( oxo aldehydes ) and products derived there from [1-6]. This method also leads to synthetically useful aldehydes and more recently is widely applied in the synthesis of more complex target molecules [7-15,17], including stereoselective and asymmetric syntheses [18-22]. 

Hydrogen cyanide undergoes many important organic reactions forming a variety of industrial products. Probably the most important reaction is the addition of the carbonyl ( =C=0) group. It adds to the carbonyl groups of aldehydes and most ketones forming cyanohydrins ... 

In tile industrial production of higher alcohols (above butyls), aldehydes play the role of an intermediate in a complete process that involves aldol condensation and hydrogenation. In the OXO process, olefins are catalytically converted into aldehydes that contain one more carbon titan the olefin in the feedstock. Aldehydes also serve as starting materials in the synthesis of several amino acids. See also Acetaldehyde Aldol Condensation Benzaldehyde and Furfuraldehyde. 

There are several laboratory-size methods for synthesizing amino acids, but few of these have been scaled up for industrial production. Glycine and m.-alanine are made by the Stnecker synthesis, commencing with formaldehyde and acetaldehyde, respectively. In tile Strecker synthesis, aldehydes react with hydrogen cyanide and excess ammonia to give amino niiriles which, in turn, are converted into a -amino adds upon hydrolysis. 

Activated alumina and phosphoric acid on a suitable support have become the choices for an industrial process. Zinc oxide with alumina has also been claimed to be a good catalyst. The actual mechanism of dehydration is not known. In industrial production, the ethylene yield is 94 to 99% of the theoretical value depending on the processing scheme. Traces of aldehyde, acids, higher hydrocarbons, and carbon oxides, as well as water, have to be removed. Fixed-bed processes developed at the beginning of this century have been commercialized in many countries, and small-scale industries are still in operation in Brazil and India. New fluid-bed processes have been developed to reduce the plant investment and operating costs (102,103). Commercially available processes include the Lummus processes (fixed and fluidized-bed processes), Halcon/Scientific Design process, NIKK/JGC process, and the Petrobras process. In all these processes, typical ethylene yield is between 94 and 99%. 

As described above, hydrolysis of the optically active enamine 3 proceeds without racemization and produces an optically active aldehyde, citronellal, with a very high optical purity (>98% ee). The optical purity of citronellal) available from natural sources is known to be no more than 80% ee [5], The present asymmetric isomerization of the allylamine 1 is utilized as the key step for the industrial production of (-)-menthol (Scheme 3.3). 

The discovery of these carbonylation processes enabled the industrial production of aldehydes, carboxylic acids or esters, and alcohols from alkenes and alkynes using Fe,... 

The direct catalyzed or uncatalyzed oxidation of alkanes with oxygen is an important reaction in the industrial production of carboxylic acids, hydroperoxides (for production of epoxides from alkenes), alcohols, ketones, or aldehydes [60],... 

The onset of the industrial production of essential oils can be dated back to the first half of the 19 century. After the importance of single aroma chemicals was recognised in the middle of the century, efforts were started to isolate such compounds from corresponding natural resources for the first time. This was soon followed by the synthesis of aroma chemicals. In this context, the most important pioneers of synthetic aroma chemicals have to be mentioned, such as methyl salicylate [1843], cinnamon aldehyde [1856], benzyl aldehyde [1863] and vanillin [1872], as they constitute the precursors of a rapidly growing number of synthetically produced (nature-identical) aroma chemicals in the ensuing years. 

Co2(CO)8 is a catalyst precursor in the hydroformylation (oxo reaction) of alkenes to give aldehydes [5], The active catalytic species generated in situ is proposed to be HCofCO),. In industry, production of butanal is performed by this homogeneous catalytic reaction. PBuj is added to increase a n/iso ratio of the aldehydes (eq (2)). 

The Karl Fischer method is applied in a multitude of substances from finished products (butter, cheese, dried milk sugar, etc.) to solvents and other industrial products (paper, gas, petroleum, plastic films, etc.). Solids and not soluble samples must, prior to the measurement, either be ground into powders, extracted with anhydrous solvents, eliminated as azeotropes or heated to evaporate the water in special accessories. The only difficult cases are encountered with strongly acidic or basic media since they denature reactants as well as ketones and aldehydes which perturb the titration through formation of acetals (special reagents must be used for these instances). 

This hydrocarboration method is a valuable tool in industrial and laboratory synthesis, since it allows introduction of the one-carbon unit of carbon monoxide into unsaturated substrates and construction of new carbon skeletons with aldehyde functions or derivatives thereof formed by reduction, oxidation, condensation and other conversions. Hydroformylation, mainly catalyzed by cobalt, rhodium, or platinum complexes is an unsymmetrical 1,2-addition leading to linear and branched products if terminal olefins are used as the substrate. Since linear products are normally the industrial products wanted54, considerable efforts have concentrated on the control of regiochemistry. Other problems of the hydroformylation method arise from side reactions such as hydrogenation, double bond migration, and subsequent reactions of the products (e.g., condensation, reduction, dccarbonylation)54. 

Since carotenoid synthesis began, the enol ether condensation has frequently been used for the formation of carbon-carbon double bonds and this reaction was also applied for large-scale industrial production of carotenoids. The reaction is an addition of an enol ether 12 to an acetal 13, promoted by a Lewis acid, especially BFa-etherate or ZnCl2, and involves a chain lengthening of two or more carbon atoms to yield an intermediary 3-alkoxyacetal 14 which subsequently is converted into an unsaturated aldehyde 15 (Scheme 3). 

Industrially, the rhodium-catalyzed hydroformylation is normally operated at about 100°, at pressures up to 50 atm and in the presence of a large excess of added phosphorus ligand, it can be carried out in molten PPhs. Under these conditions, a terminal olefin can be converted in over 90% yield to linear aldehyde. By-products include branched aldehydes as well as small amounts of alkanes and isomerized olefins. Advantages over the more conventional cobalt catalysts include lower temperatures and pressures, higher ratios of linear to branched products, and less hydrogenation of aldehyde products to alcohols. 

This reaction has extensive application in the industrial production of aldehydes and alcohols with carbon chains from C4 to... 

The preparation of ketones in particular of asymetrically substituted ketones from aldehydes is desirable since the latter are readily available, for example via the oxo-synthesis. Isomerizations of this type, for example over catalysts of mixed oxides containing tin, molybdenum and copper, are known. The disadvantages here are that only low selectivities are achieved at satisfactory conversions, and the best results with regard to selectivity and catalyst life can be obtained only with the addition of steam. Therefor, in the industrial production of asymmetrically substituted ketones, it was necessary to use the condensation of different organic acids with decarboxylation. In this process, the inevitable production of symmetrically substituted ketones and of carbon dioxide is a disadvantage. ATdol condensation with subsequent hydrogenation is another possibility but requires very often two reaction stages. 

Recently, further improved yeast systems were reported [395]. These included, among others, CYP71AV1 and an alcohol dehydrogenase and aldehyde dehydrogenase (Adhl and AldHl) from A. annua for the respective conversion of artemisinic alcohol and aldehyde [396]. Titers of artemisinic acid of up to 25 g L were achieved in fermentation experiments and could be further converted to artemisinin by means of classical chemistry or photochemistry [395]. This semisynthetic process is now used at Sanofi for the industrial production of artemisinin. 

Applications and uses. Carbon monoxide is a major industrial gas that has many applications in bulk chemicals manufacturing, including the production of methanol by hydrogenation and aldehydes by the hydroformylation reaction. It is also used in the industrial production of phosgene. Carbon monoxide and methanol react in the presence of a homogeneous rhodium catalyst and HI to give acetic acid in the Monsanto process, which is responsible for most of the industrial production of acetic acid. 

The use of 150nm-size Ag20/CuO and CuO catalysts was found to catalyze the oxidation of aromatic and aliphatic aldehydes to their corresponding acids by molecular oxygen in good yields [24]. This method has been used in the industrial production of furoic acid, although the obvious choice in this case would be CuO because of easy collection and regeneration of the catalyst... 

Very recently, a further improved yeast system was reported, which induded, among other optimizations and besides CYP71AV1, an alcohol and aldehyde [119] dehydrogenases (ADHl and ALDHl) from A. annua for artemisinic alcohol and aldehyde conversion, respectively (Scheme 5.28). Artemisinic acid titers of up to 25gl i were achieved in fermentation set-up [120]. A process based on the developed artemisinic acid-producing yeast strain is now used for the industrial production of artemisinin at Sanofi (www.rsc.org/chemistryworld/2013/04/sanqfi-launches-malaria-drug-production). 

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