Carbonate route

The basis of this process was the injection of sodium carbonate solution into the viscose, although direct injection of carbon dioxide gas that reacts with the viscose soda to form sodium carbonate could also be used (44). The carbonate route yielded a family of inflated fibers culminating in the absorbent multilimbed super inflated (SI) fiber (Eig. 5c). 

Preparative routes to aziridines and 1-azirines are derived from cycloelimination processes in which one, and sometimes two, bonds are formed directly to the nitrogen atom (Scheme 1). For aziridines these include the two intramolecular cyclization pathways involving either nucleophilic displacement by the amine nitrogen (or nitrenium anion) on the /3-carbon (route a) or nucleophilic displacement by a /3-carbanionic centre on the amine nitrogen... 

Which has been studied on supported Ni catalysts and on Ni films . Studies such as those described here show that methane can be catalytically synthesized over Ni by an active (carbidic) carbon formed via the Boudouard reaction and its subsequent hydrogenation to methane. However, to demonstrate that this surface carbon route is the major reaction pathway, kinetic measurements of both carbon formation from CO and its removal by H2 were carried out . 

In the first set of measurements the rate of carbon build-up on a Ni(lOO) surface was measured at various temperatures as follows (1) surface cleanliness was established by AES (2) the sample was retracted into the reaction chamber and exposed to several torr of CO for various times at a given temperature (3) after evacuation the sample was transferred to the analysis chamber and (4) the AES spectra of C and Ni were measured. Two features of this study are noteworthy. First, two kinds of carbon forms are evident - a carbidic type which occurs at temperatures < 650 K and a graphite type at temperatures > 650 K. The carbide form saturates at 0.5 monolayers. Second, the carbon formation data from CO disproportionation indicates a rate equivalent to that observed for methane formation in a H2/CO mixture. Therefore, the surface carbon route to product is sufficiently rapid to account for methane production with the assumption that kinetic limitations are not imposed by the hydrogenation of this surface carbon. 

A second set of experiments further supported the surface carbon route to methane. In these experiments a Ni(lOO) surface was precarbided by exposure to CO and then treated with hydrogen in the reaction chamber for various times. Steps (3) and (4) above were then followed to measure the carbide level This study showed that the rate of carbon removal in hydrogen compared favorably to the carbide formation rate in CO and to the overall methanation rate in H2/CO mixtures. Thus in a H2-CO atmosphere the reaction rate is determined by a delicate balance of the carbon formation and removal steps and neither of these is rate determining in the usual sense. 

A -M -substituted Carbonates route A, M -nitrates, 1000-1200 Ba,La-p-Al203 or Catalytic 22-24,... 

Ba-hexaaluminate via carbonates route BaAl204 + y-ai2o3 Ba-p-Al203 + traces of BaAl204 Ba-fi-Al203 -3- 120 ... 

The characterization data obtained for the carbonate route prove that the intermediate formation of well crystallized BaAl204 does not prevent the production of materials with high surface area. 

Groppi and co-workers46,26 investigated the catalytic activity of Mn- and Fe-substituted hexaaluminates prepared via the carbonate route for CO and H2 combustion. These species are the main components of fuels from gasification of carbon and biomasses that represent an alternative to natural gas in gas turbine applications. 

Both, the Kolbe-Schmitt reaction and the dialkyl carbonate route may be beneficial, notably when taking into account the former syntheses used to produce these carboxylato derivatives. Prior to the study of Tommasi et al., the formation of imi-dazolium carboxylates via highly reactive N-heterocydic carbenes (NHC) had been reported, although this rather challenging synthesis could not be extended to an industrial scale. The synthesis of l,3-diisopropyl-4,5-dimethyl-imidazohum-... 

Fig. 13. Electrochemical cell for ozone synthesis using the HBF4/glassy carbon route. (Adapted from [66]).

Now is the time to choose which of our two rearrangements to electrophilic carbon route to use. The Dn crosscheck passes, the p aHL of the leaving group is below zero, the carbocation is tertiary, and the solvent is polar. We can proceed with the Dn step. 

Selected metal oxides prepared by the activated carbon route. For further information see... 

Several variants on the dialkyl carbonate route to carbamates have been reported (2.13). Valli and Alper may have made the carbonate in situ.40... 

DISPOSAL AND STORAGE METHODS add lime to preeipitate basic lead carbonate and adsorb on aetivated carbon route to metal salvage facility store in sealed containers, plastic garbage cans with lids, or similar containers separate from strong oxidizers, hydrogen peroxide, and acids. 

Figure 1. Schematic of the cell used in the synthesis of ozone using the HBF4/Glassy Carbon route [51]. (By permission from Chapman and Hall)...

The earlier flux analyses based on positional enrichment patterns did not succeed in resolving the two C3-carboxylating enzymes phosphoeno/pyruvate carboxylase (PEPCx) and pyruvate carboxylase (PyrCx) because the carbon routes in both reactions to oxaloacetate are identical and because no differences... 

Zevenhoven, R., S. Eloneva, S. Tier, Chemical fixation ofC02 in carbonates Routes to valuable products, and long-term storage. Catal. Today, 115 (2006) 73. 

Schwickardi, M Johann, T., Schmidt, W., and Schuth, F. (2002) High-surfece-area oxides obtained by an activated carbon route. Chem. Mater., 14 (9), 3913-3919. 

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