Tetraethylammonium hydroxide, and

Protecting groups were removed by treatment of the polymer with sodium methoxide in p-dioxane, followed by tetraethylammonium hydroxide. Although nitrogen-free polymers were obtained by this procedure, the polymers had suffered a 16-20% decrease in PH. The resulting polymers were insoluble in water, sodium hydroxide, N, -dimethylformamide, and methyl sulfoxide, but were soluble in tetraethylammonium hydroxide and in Schweizer reagent. 

Mobile phase MeCN MeOH buffer 10 9 100 (Buffer was 15.54 g tetraethylammonium hydroxide and 2.9 g 89% orthophosphoric acid in 500 mL water, pH was 2.8.) Flowrate 1.2 Injection volume 50 Detector UV 271... 

VII. Mobile phase, aq. soln. containing 1 mM tri-octylmethylanunonium hydrogen chloride, 1 mM tetraethylammonium hydroxide and 5% acetonitrile in 10 m A/ sodium pho hate buffer flow-rate, 0.8 ml/min temperature, 55°... 

The electrolysis was stopped after a 7.5% solution of tetrabutyl-ammonium hydroxide had been obtained in the cathode compartment. The yield of the compound amounted to 96-99% and the current 3deld to 15%. The current density did not exceed 3 A/dm, and the temperature of the solution amounted to 25-30 C. Hydrogen was formed at the steel cathode, and iodine was liberated at the graphite anode, which was immersed in 2% sulfuric acid solution. The authors showed that tetramethyl- and tetraethylammonium hydroxides, and also butylhexylamine hydroxide, can be obtained by a similar method. 

As expected, HTMAB made a respectable showing in these experiments. Trioctylmethylammonium chloride (TOMAC) and trioctylmetliylammonium bromide (TOMAB) outperformed all other catalysts. It was postulated that the three octyl groups were the proper length for solvation of the polymer while at the same time small enough to avoid sterically hindering the reaction. In order to determine if TOMAB could be used to catalyze PET depolymerization for more than one treatment cycle, the catalyst was recovered upon completion of one treatment and added to a second run for 60 min. Tetraethylammonium hydroxide (TEAOH) was studied as a catalyst in order to demonstrate the effect of hydroxide ion as a counterion. The percent PET conversion for the second cycle was 85.7% compared to a conversion of 90.4% for the first treatment cycle. 

In a 300-mL round-bottom flask, a 5% sodium hydroxide solution (250 mL) was heated to 80° C in a constant-temperature bath. The catalysts were added in the following amounts in separate experiments trioctylmethy-lammonium chloride (TOMAC) (0.04 g, 0.0001 mol) trioctylmethylammo-nium bromide (TOMAB) (0.045 g, 0.0001 mol) hexadecyltrimethylammo-nium bromide (HTMAB) (0.045 g, 0.0001 mol) tetraethylammonium hydroxide (TEAOH) (0.015 g, 0.0001 mol) and phenyltrimethylammonium chloride (PTMAC) (0.02 g, 0.0001 mol). PET fibers (1.98 g, 0.01 mol) were added to the mixture and allowed to react for 30, 60, 90, 150, and 240 min. Upon filtration, any remaining fibers were washed several times with water, dried in an oven at 130-150°C, and weighed. The results are shown in Table 10.1. 

The exact nature of the zeolite is determined by the reaction conditions, the silica to alumina ratio and the base used. For example zeolite /3, a class of zeolites with relatively large pores, in the range of 0.7 nm, of which mordenite is an example, are usually made using tetraethylammonium hydroxide as the base. This acts as a template for the formation of 12-membered ring apertures (Figure 4.3). 

In an attempt to produce TS-1 at low cost, alternative, cheaper sources of Ti and Si and other bases such as binary mixtures of (tetrabutylammonium and tetraethylammonium hydroxides), (tetrabutylphosphonium and tetraethylpho-sphonium hydroxides), (tetrapropylammonium bromide and ammonia, water, hexanediamine, n-butylamine, diethylamine, ethylenediamine, or triethanolamine) in place of TPAOH have been used (284—294). TS-1 was synthesized in the presence of fluoride ions but the material thus formed contained extraframework Ti species (295-297). 

The application of phase-transfer catalysis to the Williamson synthesis of ethers has been exploited widely and is far superior to any classical method for the synthesis of aliphatic ethers. Probably the first example of the use of a quaternary ammonium salt to promote a nucleophilic substitution reaction is the formation of a benzyl ether using a stoichiometric amount of tetraethylammonium hydroxide [1]. Starks mentions the potential value of the quaternary ammonium catalyst for Williamson synthesis of ethers [2] and its versatility in the synthesis of methyl ethers and other alkyl ethers was soon established [3-5]. The procedure has considerable advantages over the classical Williamson synthesis both in reaction time and yields and is certainly more convenient than the use of diazomethane for the preparation of methyl ethers. Under liquidrliquid two-phase conditions, tertiary and secondary alcohols react less readily than do primary alcohols, and secondary alkyl halides tend to be ineffective. However, reactions which one might expect to be sterically inhibited are successful under phase-transfer catalytic conditions [e.g. 6]. Microwave irradiation and solidrliquid phase-transfer catalytic conditions reduce reaction times considerably [7]. 

A series of Beta zeolites have been synthesized in the presence of tetraethylammonium hydroxide (TEA). Samples with Si/Al ratio in the 7-100 range have been characterized by X-ray powder diffraction, I.R. spectroscopy, and pyridine adsorption. The fraction of TEA which is compensating the charge of the framework aluminum is removed at temperatures higher than those required to remove "occluded" TEA. Three hydroxyl bands are observed at 3740 cm l (silanol groups), 3680 cm" (extraframework Al) and 3615 cm 1 (acid hydroxyl groups interacting with pyridine). 

Total hydrolysis of the polymers gave D-glucose only. Water-soluble derivatives (ethyl or carboxymethyl ethers) of the polymers were unaffected by a-amylase, but were partially hydrolyzed by a ceUulase preparation from Acdobader xylinum. The optical rotations of several preparations of this polyglucose and of cellulose (P 1150) in tetraethylammonium hydroxide were all 0°, thereby strongly suggesting that the polyglucoses are /S-D-linked.109... 

Ion-pair chromatography has also been used for the determination of dulcin. Wu et al. (47) added the ion pair tetraethylammonium hydroxide to the mobile-phase methanol 85% phosphoric acid, pH 6 (2 8), for the separation of dulcin from saccharin, cyclamate, aspartame, and acesulfame-K on /xBondapak 08. Herrmann et al. (24) separated dulcin from saccharin, cyclamate, and aspartame on Hypersil MOS 3 using a mobile phase consisting of 5 mM tetrabutylam-... 

Abbreviations p, ratio between ionic radii of cation and anion TBHP, rm-butyl hydroperoxide EBHP, ethylbenzene hydroperoxide PO, propylene oxide TBOT, tetrabutyl orthotitanate TEOT, tetraethyl orthotitanate TIOT, tetraisopropyl orthotitanate TEOS, tetraethyl orthosilicate THF, tetrahydrofuran TPA-OH, tetrapropylammonium hydroxide TMOS, tetramethyl orthosilicate TBA-OH, tetrabutylammonium hydroxide TBP-OH, tetrabutylphophonium hydroxide TEA-OH, tetraethylammonium hydroxide TMA-OH, tetramethylammonium hydroxide. 

The 2-benzazepin-3-ones 259 have been made in moderate yields by sequential intramolecular acid-catalyzed addition followed by thiol elimination from the precursor phenylsulfanylacrylamides 258 (Scheme 33). The acrylamides 258 were prepared from reaction of the benzylamines 255 with the PNB-ester 256 to give the amides 257, and then N-methylation with Mel in the presence of potassium hydroxide and tetraethylammonium bromide, as a phase-transfer catalyst. Other noncyclized products were also observed depending on the structure of the A-aryl methyl group in 258 and on the nature of the solvent <2002H(57)1063>. 

Figure 8.6 Voltammograms for the oxidation of dissolved H2 (1 atm) in DMF [(0.5 M TEAP) (EUNCIOJ] and with 20 raM additions of triethylamine (Et3N), tetraethyl-ammonium benzoate (PhC(O)O-), and tetraethylammonium hydroxide (HO-). The Pt electrode (area 0.23 cm2) was preanodized at +1.8 V versus SCE for 2 min prior to each voltammogram scan rate 0.1 V s-1.

Figure 12.2 Cyclic voltammograms of (a) 2.0 mM 3,5-di-rert-butyl-o-benzoquinone (b) 2.0 mM, 3,5-di-ferf-butyl-o-semiquinone anion (formed by controlled potential electrolysis at —0.80 V (c) solution b plus 2.0 mM tetraethylammonium hydroxide, initial cathodic scan and (d) solution c, initial anodic scan. All solutions were in dimethyl-formamide that contained 0.1 M TEAP at a Pt electrode (surface area 0.23 cm2). Scan rate was 0.1 V s-1.

The tetraalkylammonium hydroxides (TAA) including tetramethylammonium hydroxide (TMA), tetraethylammonium hydroxide (TEA), tetrapropylammonium hydroxide (TPA), and tetrabutylammonium hydroxide (TEA) and diamines (DA) like ethylenediamine (en), 1,6-diaminohexane (1,6-DHA), and 1,10-diaminooctane (1,10-DO A) were used to intercalate into the layers of H-OL-1. The TAA or DA was added to the gel of H-OL-1. The whole mixture was stirred for certain times and the resultant nanometer-sized and larger sized colloids or sols were characterized. 

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