Alkenes economic importance

Hydrocyanation represents a reaction of considerable economic importance largely due to the value of the DuPont process involving HCN addition to butadiene to afford adiponitrile.61,62 The mechanism is well known, and involves (i) oxidative addition of H-CN to a coordinatively unsaturated metal complex, (ii) coordination of an alkene to the H-M-CN species, (iii) migratory... 

Also referred to as the oxo process or hydrocarbonylation, hydroformylation is a route to producing an aldehyde from an alkene, hydrogen, and carbon monoxide. This process has been known for approximately 70 years, and it is still economically important because useful compounds are produced in enormous quantities by this means. The reaction is summarized by the following equation ... 

Another biologically important epoxide is disparlure (4), the pheromone of the gypsy moth. This economically important insect epoxidizes a straight-chain alkene to produce just one enantiomer. The epoxide is required to be displayed as a single enantiomer to be attractive59. 

The negative signs for both AH° and AS " in typical addition reactions of alkenes cause the competition between addition and elimination to be strongly temperature-dependent. Addition is favored at low temperatures, elimination at high temperatures. The economically important hydrogenation-dehydrogenation equilibrium that connects ethylene and ethane illustrates this. 

Although the alkenes will readily undergo combustion, their primary reaction is addition reactions, A double bond is very reactive. One of the bonds can easily be broken, and the two carbons can then form new single bonds to other atoms. One of the most economically important addition reactions is... 

In their polymerization, many individual alkene molecules combine to give a high-molecular-weight product. Several economically important polymCTs are prepared by free-radical processes. 

The design of a general and efficient process for the hydroamination of alkenes would be a very important (economic) breakthrough for the production of amines. A... 

It should be mentioned that many of the requirements necessary for the economic production of polyethylene and polypropylene have been achieved. However, catalysts of greater activity and of greater selectivity in the production of polymers and copolymers can be anticipated. This is of prime concern to alkene polymerisation processes in the presence of single-site metallocene catalysts. Such catalysts, undoubtedly of great scientific and commercial importance, have been developed on a large scale within recent years [29,30],... 

Stoichiometric and catalytic transition-metal oxidation reactions are of great interest, because of their important role in industrial and synthetic processes. The oxidation of alkenes is one of the fundamental reactions in chemistry.1 Most bulk organic products contain functional groups, which are produced in the chemical industry by direct oxidation of the hydrocarbon feedstock. Usually these reactions employ catalysts to improve the yields, to reduce the necessary activation energy and render the reaction more economic. The synthesis of almost every product in chemical industry nowadays employs at least one catalytic step. The oxidation products of alkenes, epoxides and glycols, may be transformed into a variety of functional groups and therefore the selective and catalytic oxidation of alkenes is an industrially important process. 

While hydrocyanation, the addition of HCN to an unsaturated substrate, is not the only method of producing an organonitrile, it is often the easiest and most economical. The addition of HCN to aldehydes and ketones is readily accomplished with simple base catalysis, as is its addition to activated aUcenes (Michael addition). However, the addition of HCN to unactivated alkenes and dienes is best accomplished with a transition metal catalyst. The hydrocyanation of alkenes and dienes is the most important way to prepare nitriles and is the focus of this article. 

Aliphatic amines are amongst the most important bulk and fine chemicals in the chemical and pharmaceutical industry [13]. Hydroaminomethylation of alkenes to amines presents an atom-economic, efficient and elegant synthetic pathway towards this class of compounds. In hydroaminomethylation a reaction sequence of hydroformylation of an alkene to an aldehyde with subsequent reductive amina-tion proceeds in a domino reaction (see Eq. 4) [14]. Recently, the highly selective hydroamination of alkenes with ammonia to form linear primary and secondary aliphatic amines with a new Rh/Ir catalytic system (] Rh(cod)Cl 2], ] Ir(cod)Cl 2], aqueous TPPTS solution) has been described (see Scheme 2) [15]. The method is of particular importance for the production of industrially relevant, low molecular weight amines. 

Since the introduction of the first peptide organocatalyst in the 1980s, a considerable number of new peptide frameworks have been developed that are able to effectively catalyse several important transformations including alcohol esterifications, 1,4-conjugate additions, aldol reactions, Strecker synthesis, asymmetric cyanohydrin synthesis and alkene epoxidation are discussed. A few successful examples of solid-supported peptides and reactions in ball milling under solvent-free conditions have been demonstrated. These methods combine the advantages of being economically and environmentally friendly processes. 

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