3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Chemical Routes for the Transformation of Biomass into Chemicals

4.3. Reaction Mechanism 2373 4.4. Asymmetric Synthesis 2374 4.5. Outlook 2374 5. Alternating Polymerization of Oxiranes and CO2 2374 5.1. Reaction Outlines 2374 5.2. Catalyst 2376 5.3. Asymmetric Polymerization 2377 5.4. Immobilized Catalysts 2377 6. Synthesis of Urea and Urethane Derivatives 2378 7. Synthesis of Carboxylic Acid 2379 8. Synthesis of Esters and Lactones 2380 9. Synthesis of Isocyanates 2382 10. Hydrogenation and Hydroformylation, and Alcohol Homologation 2382

Transformation of carbon dioxide.

Water near or above its critical point (374 C, 218 atm) is attracting increased attention as a medium for organic chemistry. Most of this new attention is driven by the search for more green or environmentally benign chemical processes. Using near-critical or supercritical water (SCW) instead of organic solvents in chemical processes offers environmental advantages and may lead to pollution prevention. Interest in doing chemistry in SCW is not entirely new, however. There has been much previous research in this area with applications in synthetic fuels production, biomass processing, waste treatment, materials synthesis, and geochemistry. Water near its critical point possesses properties very different from those of ambient liquid water. The dielectric constant is much lower, and the number and persistence of hydrogen bonds are both diminished. As a result, high-temperature water behaves like many organic solvents in that organic compounds enjoy high solubilities in near-critical water and complete miscibility with SCW. Moreover, gases are also miscible in SCW so employing a SCW reaction environment provides an opportunity to conduct chemistry in a single fluid phase that would otherwise occur in a multiphase system under more conventional conditions. The paper discusses the use of supercritical water in the following reactions:more » hydrogenation/dehydrogenation; C-C bond formation; rearrangements; hydration/dehydration; elimination; hydrolysis; partial oxidation; H-D exchange; decomposition; and oxidation.« less

Organic Chemical Reactions in Supercritical Water.

Hydrogen autotransfer in the N-alkylation of amines and related compounds using alcohols and amines as electrophiles.

Alcohols can be temporarily converted into carbonyl compounds by the metal-catalysed removal of hydrogen. The carbonyl compounds are reactive in a wider range of transformations than the precursor alcohols and can react in situ to give imines, alkenes, and α-functionalised carbonyl compounds. The metal catalyst, which had borrowed the hydrogen, then returns it to the transformed carbonyl compound, leading to an overall process in which alcohols can be converted into amines, compounds containing CC bonds and β-functionalised alcohols.

Borrowing hydrogen in the activation of alcohols

/pdf/depolymerization-of-polyethylene-terephthalate-to-monomers-3gr7gt9944.pdf

Depolymerization of Polyethylene Terephthalate to Monomers with Supercritical Methanol

To obtain fundamental data for the extraction and concentration of furfural produced in a reactor by using supercritical CO2, the isothermal high pressure vapor–liquid equilibria for two binary systems (CO2–water and CO2–furfural) and a ternary system (CO2–water–furfural) were measured in the temperature range from 343 to 421 K. Additionally, the experimental data were compared with results calculated by various equations of state. As a result, it was found that (1) the Peng–Robinson and Soave–Redlich–Kwong equations of state combined with the mixing rules proposed by Panagiotopoulos correlated the two binary systems satisfactorily and predicted the ternary system well, and (2) the furfural produced could be selectively extracted from the reactor and concentrated to 95 wt% by a new process proposed on the basis of a knowledge of the vapor–liquid equilibria.

Phase Equilibrium Study of Extraction and Concentration of Furfural Produced in Reactor Using Supercritical Carbon Dioxide

In this study, we tried to decompose the dioxins in a fly ash using supercritical water and an oxidizer. The first objective is to compare the decomposition efficiency of the dioxins in the fly ash with that in the pulp mill sludge, because the distribution pattern of the dioxin isomers in the fly ash (called incineration pattern) is quite different from that in the pulp mill sludge (pulp bleaching pattern) (Hiraoka, 1993), that is, the former has many kinds of dioxin isomers and the latter contains relatively high concentrations of tetrachlorodibenzofuran and tetrachlorodibenso-p-dioxin. The second objective is to check the possibility of the decomposition of dioxins at around 673 K because a conventional stainless steel can be used as a construction material for the decomposition reactor in a very dilute aqueous region of hydrogen chloride. The third objective is to examine what kind of oxidizer is suitable for rapid and complete decomposition of the dioxins.

/pdf/decomposition-of-dioxins-in-fly-ash-with-supercritical-water-27pp00b8ea.pdf

Decomposition of Dioxins in Fly Ash with Supercritical Water Oxidation

Recovery of Constituent Monomers from Polyethylene Terephthalate with Supercritical Methanol

/pdf/recovery-of-constituent-monomers-from-polyethylene-2i1llch19g.pdf

Recovery of constituent monomers from polyethylene terephthalate with supercritical methanol

Vapor pressures of binary (water-hydrogen chloride, -magnesium chloride, and -calcium chloride) and ternary (water-magnesium chloride-calcium chloride) aqueous solutions

Takeshi Sako

Papers

Depolymerization of Polyethylene Terephthalate to Monomers with Supercritical Methanol

Phase Equilibrium Study of Extraction and Concentration of Furfural Produced in Reactor Using Supercritical Carbon Dioxide

Decomposition of Dioxins in Fly Ash with Supercritical Water Oxidation

Recovery of constituent monomers from polyethylene terephthalate with supercritical methanol

Vapor pressures of binary (water-hydrogen chloride, -magnesium chloride, and -calcium chloride) and ternary (water-magnesium chloride-calcium chloride) aqueous solutions