Multicomponent mixtures sequential reactions

Multicomponent reactions (MCRs) are processes that involve sequential reactions among three or more reactant components that co-exist in the same reaction mixture. In order to be efficient, MCRs rely on components that are compatible with each other and do not undergo alternative irreversible reactions to form other products or by-products. 

There are at least four general types of combinations of crosslinked (x) and linear (1) polymers in a two-component system both components crosslinked (xx), one or the other component crosslinked (lx or xl), and both components linear (11). Where at least one of the components has been polymerized in the presence of the other, the xx forms have often been called interpenetrating polymer networks (IPN), the lx and the xl forms termed "semi-IPNs", and the last, linear or in situ blends. There are also a number of ways in which the components can be formed and assembled into a multicomponent system. Sequential IPNs are prepared by swelling one network polymer with the precursors of the second and polymerizing. Simultaneous IPNs are formed from a mixture of the precursors of both components polymerization to form each component by independent reactions is carried out in the presence of the other precursors or products. Usually, the simultaneous IPNs that have been reported are extremes in the component formation sequence the first component is formed before the second polymerization is begun. Sequential IPNs and simultaneous IPNs of the same composition do not necessarily have the same morphology and properties. 

Tandem domino and tandem consecutive reactions do not necessarily involve more than one reactant and can be unimolecular, as is exemplified by such processes as polyolefin cyclization [13]. Tandem sequential reactions cannot be unimolecular processes and involve two reactants at least. Both, tandem sequential and higher-order tandem domino reactions are of foremost interest in this text, because they enable the concept of multicomponent reactions (MCRs) to be introduced [4, 7-9]. Depending on the reaction conditions, MCRs can be regarded as a subclass of either tandem sequential (Scheme 17.1a) or higher order tandem domino reactions (Scheme 17.1b). In the former, formation of intermediate AB is followed by addition of a third component C to the reaction mixture to enable formation of reaction product ABC. In the latter, components A, B, and C are simply... 

Information about the monomeric composition and structure can be obtained with pyrolysis MS but sequence information is lost [46]. The method was used in several applications, such as structural identification of homopolymers, differentiation of isomeric structures, copolymer composition and sequential analysis, identification of oligomers formed in the polymerization reactions, and identification of volatile additives contained in polymer samples [47]. One of the main challenges of the technique is the identification of the products in the spectrum of the multicomponent mixture produced by thermal degradation. 

This approach uses a kinetic sequential principle to carry out multicomponent CL-based determinations. In fact, when the half-lives of the CL reactions involved in the determination of the analytes in mixture are appreciably different, the CL intensity-versus-time curve exhibits two peaks that are separate in time (in the case of a binary mixture) this allows both analytes to be directly determined from their corresponding calibration plots. In general, commercially available chemiluminometers have been used in these determinations, so the CL reaction was initially started by addition of one or two reaction ingredients. Thus, in the analysis of binary mixtures of cysteine and gluthatione, appropriate time-resolved response curves were obtained provided that equal volumes of peroxidase and luminol were mixed and saturated with oxygen and that copper(H) and aminothiol solutions were simultaneously injected [62, 63],... 

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