Regenerative schemes

Voltage source inverter (VSl) using IGBTs 6/125 Current source inverter (CSl) 6/126 Cyclo converters (frequency converters) 6/127 The regenerative schemes 6/127... 

The scheme will also facilitate conservation of regenerative energy if there are more of such drives without any additional cost. 

Figure 5.58 presents a general scheme of photogalvanic cells based on reductive (a) or oxidative (b) quenching of S. These cells are regenerative if D and A are two forms of the same redox couple (D+ =A and D =A ), otherwise the products D+ and A accumulate in the electrolyte and the cell is photoelectrosynthetic. 

To date, electrochemical C02 transport has not been applied to situations other than manned spacecraft life support. It appears possible that commercial MCFC s can provide an economical means for providing food-grade C02 [34]. In this scheme (Fig. 23b) the MCFC acts as a concentrator for C02 (and some 02) from the flue gas emitted from a power plant burning relatively clean fuel (e.g. natural gas). Electric power input is required, as is considerable regenerative heat exchange. Despite these charges, the process would be economical if the MCFC stacks become commercially available at projected prices [34]. 

It should be noted that the reaction of benzalde-hyde with (Z)-3-trimethylsiloxy-2-pentene in ethanol or dichloromethane in the presence of the chiral catalyst resulted in a much lower yield and selectivity. On the basis of these results, we propose the catalytic cycle shown in Scheme 2. The catalyst A formed from Cu(OTf)2 and a bis(oxazoline) ligand accelerates the aldol reaction to generate the intermediate B. In aqueous solvents, B is rapidly hydrolyzed to produce the aldol product C and regener-... 

If the follow-up chemical reactions regenerate the initial electroactive reactant, the mechanism (2.178) is transformed into a regenerative catalytic mechanism as represented by the following scheme [130] ... 

The regenerative part of the PPP is only shown here schematically. A complete reaction scheme is given on p. 408. The function... 

The isomeric 2-benzyl-3-methyl-pyrazole 1-oxide 193 reacts similarly to give the 3-iodomethyl-pyrazole 196. In this case, the 3-trimethylsilyloxy-methyl compound 197 is formed as a by-product. Most likely, the sily-loxymethyl compound 197 arises when the liberated silyloxyanion acts as a nucleophile replacing the silyloxy group in a regenerative fashion. The silyloxy compound 197 is readily hydrolyzed to hydroxymethyl-pyrazole 198. The 3-methyl-pyrazole 1-oxide 193 reacts five times faster than the 5-methyl isomer 189 as shown by a competition experiment (1992JCS(P1)2555). The iodomethyl-pyrazoles 192 and 196 are versatile starting materials for further transformations in the pyrazole side chain (Scheme 55). 

Catalytic current — Figure. Reaction scheme of a reductive regenerative catalytic electrode mechanism (the charge of the species is omitted)... 

Trapping the carbonyl compound 1 in Scheme 3.3 with various nucleophiles provides various catalytic oxidative transformations of alcohols. When a primary or secondary amine is employed as a nucleophile, intermediate 13 undergoes nucleophilic reaction with amine to give iminium ion complex 14 along with water. Intramolecular hydride transfer of 14 gives the corresponding N-alkylated amine 15 with regen-... 

---