Sodium form preparation

A solution of 192 g of 1 -phenethyl-4-hydroxy-4-aminomethyl piperidine in BOO cc of diethyi-carbonate is heated for 1 /i hours to refiux at about B0°C in the presence of sodium methylate (prepared for immediate use from 2 g of sodium). After this time, the ethyl alcohol formed during the reaction is slowly distilled while the maximum temperature is reached. The excess ethyl carbonate is distilled under reduced pressure. A crystallized residue Is then obtained, which is stirred with 400 cc of water and 400 cc of ether. The solution is filtered and 125 g (77.6%) of practically pure product melting at 232°C to 233°C, are obtained. 

Aerosil was converted into the sodium form by treating it with a buffer solution (pH = 8.4) made of sodium hydroxide and sodium hydrogen carbonate solutions, after which it was filtered, washed free of alkali, and dried. This sodium-exchanged aerosil was then suspended in a solution of Ni(en)3(N03)2 prepared by adding the calculated amount of ethylene-diamine to a solution of nickel nitrate. The suspension was agitated for about 30 min and filtered off. The catalyst was then washed and dried at 100°C. 

In a more simple and cheap way, silver clusters can be prepared in aqueous solutions of commercially available polyelectrolytes, such as poly(methacrylic acid) (PM A A) by photo activation using visible light [20] or UV light [29]. Ras et al. found that photoactivation with visible light results in fluorescent silver cluster solutions without any noticeable silver nanoparticle impurities, as seen in electron microscopy and from the absence of plasmon absorption bands near 400 nm (F = 5-6%). It was seen that using PMAA in its acidic form, different ratios Ag+ MAA (0.15 1-3 1) lead to different emission bands, as discussed in the next section (Fig. 12) [20]. When solutions of PMAA in its sodium form and silver salt were reduced with UV light (365 nm, 8 W), silver nanoclusters were obtained with emission band centered at 620 nm and [Pg.322]

To prepare alkali- or alkaline earth-modified zeolites or mesoporous moleeular sieves, identieal general methodologies are used. Thus, alkaline earth eation-exehanged zeolites are prepared by exehange of the zeolite in the sodium form in aqueous solution of alkaline earth metal salts, followed by washing and ealeination. Alkaline earth metal oxides loaded in zeolites are also prepared by impregnation of alkaline earth metal salts sueh as nitrates, aeetates, or ethoxides followed by ealeination (70,215,216). 

HZSM-5 was prepared through ammonium exchange of the sodium form (AF-5, Si Al =50). Pour successive exchanges were carried out for Ih with a IM NH C1 solution... 

Decationated zeolites. We start by considering decationated zeolites since they do not contain any metal ions extrinsic to the silica-alumina framework. This type of zeolite is obtained by pretreating, above 350°C, a NH4Y zeolite prepared by exchanging the sodium form of a Y-type zeolite with ammonium ions. Ammonia is evolved leaving a decationated or HY zeolite ... 

Vaughan et al. (76) and Thomas et al. (77) measured 29Si MAS NMR spectra of the sodium forms of (Si,Ga)-sodalites and (Si,Ga)-faujasites. All preparations in ref. 76 contained some aluminum (attempts at preparing completely Al-free compounds were unsuccessful), but the amounts involved were so small (less than 5%) that the influence of Al on 29Si spectra was... 

McDaniel and Maher (159-161) were the first to report that upon thermal treatment of NH4-Y, under a particular set of conditions, thermal stability of the zeolite is considerably increased. The product retains crystallinity at temperatures in excess of 1000°C, while the decomposition of the sodium form of the zeolite takes place at ca. 800°C. This process is known as ultrastabilization. Ultrastable zeolite Y is very well suited as a catalyst for hydrocracking reactions—much more so than the as-prepared zeolite, which is too acidic and has insufficient thermal stability. 

Sodium tellurite, prepared by dissolution of tellurium dioxide in aqueous sodium hydroxide, reacted with carboxymethanethiol1 and with 1-carboxy-l-ethanethiol2 to form bis[carboxyalkylthio] tellurium compounds. The reactions must be carried out in acidic solutions, because base decomposes the bis[alkylthio] tellurium derivatives. With an excess of thiol, compounds with more than two alkylthio groups bonded to the tellurium atom were observed1,2. 

Bis[tetraethylammonium] Tetrakis(benzenetellurolate] ferrate(II)3 Under an atmosphere of nitrogen, 1.83 g (4.0 mmol) bis[tetraethylammonium] tetrachloroferratc(II) dissolved in 25 ml acetone are mixed with a solution of 16 mmol sodium benzenetellurolate prepared from 3.27 g (8.0 mmol) diphenyl ditellurium and 0.61 g (16 mmol) sodium borohydride, in 10 m/ ethanol. The immediately formed red precipitate is filtered and dried under a vacuum yield 100%. 

Sodium arenetellurolates, prepared by reduction of diaryl ditelluriums with sodium borohydride, reacted with 1,4-dichlorobutane7, 1,4-dibromobutane7, and 1,5-dibromo-pentane8 forming aryl tetra- or pentamethylene telluronium halides. 

The selective adsorbent CaA is prepared in the sodium form (the detergent zeolite NaA) and subsequently partially exchanged with Ca(II). 

Series of zeolite-supported iron-containing catalysts with weight percent iron (% Fe) varying from 1 to 17% Fe have been prepared from Fe3(CO) 2 and the synthetic zeolites ZSM-5, mordenite and 13X by an extraction technique. The zeolites ZSM-5 and mordenite were used in the acid form, 13X in the sodium form. 

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