Reaction properties, fine chemical synthesis

The unique properties of zeolites and other micro- or mesoporous solids that may favour their application to fine chemical synthesis are (1) the compatibility between the size and shape of their channels or cavities with the size of the reactants and/or products (generally referred to as molecular shape selectivity) that may direct the reaction away from the thermodynamically favoured route (2) the occurrence of confinement effects increasing the concentration of reactants near the catalytic sites and (3) the ability to tune their catalytic properties (acidic, basic, or other) via various treatments as described in this Volume. 

In the last decade significant progress has been made towards the development of new catalysts for palladium chemistry [167, 168]. Since the properties of the central metal palladium can be tuned by ligand variation, the introduction of new ligands was the key to success. The refinement of economically attractive aryl-X compounds is of general interest in fine chemical synthesis. As an example, the alkenylation of aryl-X derivatives (Heck reaction) [15, 16, 24, 105, 106, 169, 170, 171-182] has been called one of the true powerful tools of contemporary organic synthesis [18]. 

Figure 7 illustrates the use of HPGPC to aid a resin chemist in developing an in-house isocyanate crosslinker for a powder coating system. Isocyanate crosslinker X-02 gave desired properties and is considered the standard. At the early stage of the development, resin X-03 was initially made. By changing the types of reactants, molar ratio of reactants and reaction conditions, resin X-36 was the next iteration in the resin synthesis process. Finally, X-36 was fine-tuned to produce X-38 which matched X-02 in both its chemical reaction properties and its MWD. 

Industrial applications of zeolites cover a broad range of technological processes from oil upgrading, via petrochemical transformations up to synthesis of fine chemicals [1,2]. These processes clearly benefit from zeolite well-defined microporous structures providing a possibility of reaction control via shape selectivity [3,4] and acidity [5]. Catalytic reactions, namely transformations of aromatic hydrocarbons via alkylation, isomerization, disproportionation and transalkylation [2], are not only of industrial importance but can also be used to assess the structural features of zeolites [6] especially when combined with the investigation of their acidic properties [7]. A high diversity of zeolitic structures provides us with the opportunity to correlate the acidity, activity and selectivity of different structural types of zeolites. 

The wide range of desired functionalities on the surface of catalysts that includes, for example, strong acid sites for cracking reaction, mild acid-base pairs for the synthesis of fine chemicals, redox properties for oxidation reactions, or metal nanoparticles for hydrogenation or electrochemical applications seems to complicate the derivation of general rules with respect to catalyst synthesis. It is, however, accepted without controversy that good catalysts feature the following characteristics ... 

Due to the interest in substituting mineral and Lewis acids in the synthesis of fine chemicals to avoid inorganic salts production, and in order to have a deeper insight into the acidic properties of our catalysts, we investigated the behaviour of the supports, in a typical acid catalyzed reaction [7], namely the ene reaction of citronellal to give the four isopulegol isomers. 

Boekelheide and Phillips815 achieved the synthesis of the interesting /ra/ .r-15,16-dimethyldihydropyrene (17) and found that by all criteria, including both spectral properties and chemical reactivity, this hydrocarbon having substituents within the cavity of the (4n + 2) electron cloud is an aromatic molecule. In their synthesis, indicated briefly in the formulation, one meta link between two molecules of (8) is established by reaction with magnesium in the presence of ferric chloride to produce the bibenzyl derivative (9). Reaction of the diiodide (14) with finely divided sodium and tetraphenylethylene in tetrahydrofurane establishes the second meta link... 

A variety of solid Lewis and Br0nsted acids has been shown to catalyze Diels-Alder reactions. In several instances the results obtained with heterogeneous catalysts were better than those with homogeneous Lewis acid catalysts. Most of the reported reactions of interest in the synthesis of fine chemicals were catalyzed by (modified) zeolites, clays, alumina, or silica. Catalysts with interesting properties were obtained when support materials such as zeolites, alumina, or silica were treated with Lewis acids. These catalysts were moderately selective in diastereo-selective Diels-Alder reactions with chiral dienophiles and induced enantioselec-tivity (up to 31 % e. e.) in the reaction of cyclopentadiene with methacrolein after treatment with chiral derivatives. Excellent enantioselectivity in this reaction (up to 95 % e. e.) was observed with a polymer-supported chiral oxazaborolidinone. Because of their facile recovery and recycling, we expect that solid-acid catalysts will find increasing use in Diels-Alder reactions in the future. 

In the present study, we will desribet the link between the nitridation parameters and the performances of oxynitrides for the synthesis of jasminaldehyde. Jasminaldehyde (a-amylcinnamaldehyde) is obtained through the aldol condensation of heptanal with benzaldehyde, in the liquid phase. It is a fine chemical of commercial interest [2], as it is used by the flavour and perfume industry. On top of its industrial interest, the aldol condensation reaction between heptanal and benzaldehyde is an interesting test reaction to assess the acid-base properties of heterogeneous catalysts. Heptanal is more reactive than... 

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