Synthesis in High-temperature Water

A diverse range of reactions were studied and high selectivity was obtained with seemingly minor variations in the conditions [31]. Scale-up was also demonstrated, including to continuous operation with the CMR [15]. This indicated the potential of aqueous high-temperature media for future development of clean processes. Ob- 

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Scheme 5.11 Indole synthesis in high temperature water...

Hunter SE, Ehrenberger CE, Savage PE. (2006). Kinetics and mechanism of telrahydrofuran synthesis via 1,4-butanediol dehydration in high-temperature water. JOrg Chem, 71,6229— 6239. 

Dudd, L.M., Venardou, E., Garcia-Verdugo, E., Licence, A.J., Blake, A.J., Wilson, C. and Poliakoff, M., Synthesis of benzimidazoles in high-temperature water, Green Chem., 2003, 5, 187-192. 

Hunter, S.E. and Savage, P.E., Recent advances in acid- and base-catalyzed organic synthesis in high-temperature liquid water, Chem. Eng. ScL, 2004,59(22/23), 4903-4909. 

LiCo02 or LiMn204 is of great importance for lithium ion battery technologies. For hydrothermal synthesis of LiCo02, where Co " " ion is a starting species, the oxidation conditions for Co + do not always match that required for the crystallization atmosphere. In most cases oxidants decomposed in high-temperature water. 

Hunter, S.E., Felezak, C.A. Savage, P.E. Synthesis of p-isopropenyphenol in high-temperature water. Green Chem. 2004, 6,222-226. 

In contrast to SCCO2, the conditions required to obtain SCH2O are harsh. In particular the temperature requirement of 374 °C precludes its synthetic utility for most organic compounds. That said, syntheses in sub-critical but high-temperature water are well studied and will be covered in the next section. Since many natural minerals and precious stones were formed in water at high temperature and pressure in the Earth s crust, the synthesis... 

In high temperature gasification processes, whether coal or oil, the oxygen is completely consumed in the reaction and no oxygen is contained in the synthesis gas. One should, however, be aware of the potential of introducing small quantities of oxygen into the gas in the subsequent processing, either in low pressure processes or via the wash water. 

Several compounds of beryllium have important applications. The most commercially important beryllium compound is beryllium oxide (BeO), which is used in high-temperature applications, such as crucibles, microwave ovens, ceramics, and insulators. Beryllium oxide also finds use in gyroscopes and military vehicle armor. Beryllium chloride (BeCl2) is used as a catalyst in the synthesis of organic chemicals. Beryllium hydride (BeH2) is a source of hydrogen gas when mixed with water. Beryllium carbide (Be2C) is a source of neutrons in nuclear reactors. 

Osada M, Savage PE. (2009) Terephthalic acid synthesis at higher concentrations in high temperature liquid water. 2. Eliminating undesired by-products. AICHEJ, 55(6) 1530-1537. 

Similarly, C o was converted into MWCNTs above 700°C via amorphous carbon under hydro-thermal conditions [119], SWCNTs under hydrothermal conditions can only survive mild- and short-term treatment in high-temperature, high-pressure water. With time, SWCNTs gradually transform into MWCNTs and polyhedral graphitic nanoparticles [35]. Both carbon filaments and MWCNTs are produced using ferrocene, Fe, or Fe/Pt nanocrystals at supercritical toluene at 600°C and 12.4 MPa. In this study, toluene serves as both the carbon source for nanotube formation and as a solvent [154]. Recently, direct synthesis of MWCNTs/CdS, MWCNT/ZnO, Ti/CNT, FeO/ MWCNTs, and CNT-F-doped Sn02 nanocomposites under hydrothermal process has been used for various applications [155-159]. 

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