Aluminates reactions with

Some reactions of the paste with aggregate have been mentioned in Sect. 6.2. It relates to the calcium aluminate reaction with calcite, which promotes the strength... 

Chemical recovery ia sodium-based sulfite pulpiag is more complicated, and a large number of processes have been proposed. The most common process iavolves liquor iaciaeration under reduciag conditions to give a smelt, which is dissolved to produce a kraft-type green liquor. Sulfide is stripped from the liquor as H2S after the pH is lowered by CO2. The H2S is oxidized to sulfur ia a separate stream by reaction with SO2, and the sulfur is subsequendy burned to reform SO2. Alternatively, ia a pyrolysis process such as SCA-Bidemd, the H2S gas is burned direcdy to SO2. A rather novel approach is the Sonoco process, ia which alumina is added to the spent liquors which are then burned ia a kiln to form sodium aluminate. In anther method, used particulady ia neutral sulfite semichemical processes, fluidized-bed combustion is employed to give a mixture of sodium carbonate and sodium sulfate, which can be sold to kraft mills as makeup chemical. 

Aluminum alkyls react by the Ziegler reaction with the least substituted double bond to give the tricitroneUyl aluminum compound. Oxidation of the iatermediate compound then produces the tricitroneUyl aluminate, which is easily hydroly2ed with water to give citroneUol (112,113). If the citroneUene is opticaUy active, opticaUy active citroneUol can be obtained (114). The (—)-citroneUol is a more valuable fragrance compound than the ( )-citroneUol. 

Barium metal and most barium compounds are highly poisonous. A notable exception is barium sulfate which is nontoxic because of its extreme iasolubihty ia water. Barium ion acts as a muscle stimulant and can cause death through ventricular fibrillation of the heart. Therefore, care must be taken to avoid contact with open areas of the skin. Workers must wear respirators (of type approved for toxic airborne particles), goggles, gloves, and protective clothing at all times. The toxic barium aluminate residue obtained from barium production is detoxified by reaction with a solution of ferrous sulfate and converted iato nontoxic barium sulfate. According to OSHA standards, the TWA value for Ba and Ba compounds ia air is 0.5 mg/m. ... 

Other reactions taking place throughout the hardening period are substitution and addition reactions (29). Ferrite and sulfoferrite analogues of calcium monosulfoaluminate and ettringite form soHd solutions in which iron oxide substitutes continuously for the alumina. Reactions with the calcium sihcate hydrate result in the formation of additional substituted C—S—H gel at the expense of the crystalline aluminate, sulfate, and ferrite hydrate phases. 

The lithium 2-butenyl(triethyl)aluminate complex, prepared in situ from 2-butenyllithium and triethylaluminum, displayed poor diastereoselectivity in a reaction with benzaldehyde (anti/syn 56 44)7. (Z)-3-Alkoxy-substituted aluminate complexes such as A-C, however, give good diastereoselectivity in aldehyde addition reactions8. The reactions of A with aldehydes at —100 °C give the jyw-diol monoether with >95% diastereoselectivity and >80-95% regiose-... 

Negishi E, Tan Z (2005) Diastereoselective, Enantioselective, and Regioselective Carbo-alumination Reactions Catalyzed by Zirconocene Derivatives. 8 139-176 Netherton M, Fu GC (2005)Pa]ladium-catalyzed Cross-Coupling Reactions of Unactivated Alkyl Electrophiles with Organometallic Compounds. 14 85-108 Nicolaou KC, King NP, He Y (1998) Ring-Closing Metathesis in the Synthesis of EpothUones and Polyether Natmal Products. 1 73-104 Nishiyama H (2004) Cyclopropanation with Ruthenium Catalysts. 11 81-92 Noels A, Demonceau A, Delaude L (2004) Ruthenium Promoted Catalysed Radical Processes toward Fine Chemistry. 11 155-171... 

Mori reported an improved synthesis of (3S,4P,6 ,10Z)-faranal (37), the trail pheromone of the Pharaoh s ant (Monomorium pharaonis) [84]. As summarized in Scheme 55, the key-reaction was the coupling of iododiene A with iodide E. The geometrically pure A was prepared by the zirconocene-mediated carbo-alumination reaction, and E was prepared from B by the asymmetric cleavage of its epoxy ring to give C (77% ee), which could be purified via its crystalline 3,5-dinitrobenzoate D. 

After extensive experimentation, a simple solution for avoiding catalyst deactivation was discovered, when testing an Ir-PHOX catalyst with tetrakis[3,5-bis (trifluoromethyl)phenyl]borate (BArp ) as counterion [5]. Iridium complexes with this bulky, apolar, and extremely weakly coordinating anion [18] did not suffer from deactivation, and full conversion could be routinely obtained with catalyst loadings as low as 0.02 mol% [19]. In addition, the BArp salts proved to be much less sensitive to moisture than the corresponding hexafluorophosphates. Tetrakis (pentafluorophenyl)borate and tetrakis(perfluoro-tert-butoxy)aluminate were equally effective with very high turnover frequency, whereas catalysts with hexafluorophosphate and tetrafluoroborate gave only low conversion while reactions with triflate were completely ineffective (Fig. 1). 

The reaction of 1-alkoxypolyfiuoroalkyl sulfonates with lithium tetraalkyl alumin ates yields stereospecifically alkylated products with a high degree of inversion. However, the reaction with trialkylaluminium reagents is considerably less stereospecific. 

The procedures described below have consistently given stable, crystalline products for a number of tertiary phosphine copper hydride complexes. These complexes can be prepared by the careful reaction of lithium tetrahydrido-aluminate(l-) with tertiary phosphine copper halide complexes. The reactions are run in etheral solvents under an inert atmosphere. The resultant products are... 

Homoaliyttc alcohols,An efficient synthesis of homoallylic alcohols of type I involves carbometallation of 1-alkynes (8, 506) followed by reaction of the alkcnyl-aluminate (a) with an epoxide.2... 

Barrer and Mainwaring (20) report the use of metakaolin as the aluminosilicate raw material for reaction with the hydroxides of K and Ba as well as the binary base systems Ba-K and Ba-TMA to form zeolites. Zeolite phases previously synthesized in the analogous hydrous aluminosilicate gel systems were crystallized with KOH, including phillipsite-, chabazite-, K-F-, and L-type structures. The barium system yielded two unidentified zeolite phases (Ba-T and Ba-N) and a species Ba-G,L with a structural resemblance to Linde zeolite L. Ba-G,L was reported previously by Barrer and Marshall (21) as Ba-G. Similar phases were formed in the Ba-K system and in the TMA-Ba system where, in addition, erionite-type phases were formed. The L-type structures are said to represent aluminous analogs of the zeolite L previously reported (22). 

It is generally believed that the silica sol consists of colloidal particles (15) the oxygen-silicon tetrahedra are present inside the particles, and the hydroxyl groups may appear only on the surface. Initially the reaction with aluminate takes place predominantly on the surface, but our results on prolonged aging and crystallization indicate that the colloidal particles decompose slowly, and this results in solid and liquid phase compositions similar to that observed if the zeolite were synthesized from metasilicate. 

The above results show that post synthesis alumination of PSM with AlfNOjfi improves the hydrothermal stability of the resulting AMM material. Similar effect has been observed by Mokaya et al. [12], who reported that the hydrothermal stability of MCM-41 could be enhanced by reaction with chlorohydrate of aluminium. Moreover, from the study of high Si/Al ratio of Y zeolite, Lutz et al. [13] reported that the hydrothermal stability of Y zeolite was enhanced by an external introduction of non-structural aluminum species onto the surface of Y zeolite. The surface layer of Al-rich aluminosilicate or aluminum oxide was suggested to block the terminal OH groups and energy-rich =Si-0-Si= bonds on the surface of Y zeolite, hence minimizing the attack of water molecules on the framework. Due to these properties, the non-structural... 

Hydroxide Aluminum hydroxide Al(OH>3, white gelatinous precipitate, by reaction of soluble, aluminum salt solution and an alkali hydroxide, carbonate or sulfide (sodium aluminate is formed with excess NaOH but no reaction with excess NH4OH). upon heating aluminum hydroxide the residue formed is aluminum oxide. Used as intermediate substance in transforming bauxite into pure aluminum oxide. 

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