Nitrogen commercial sources

The catalyst, 3-benzyl-5-(2-hydroxyethyl )-4-methyl-l, 3-thiazoHum chloride, is supplied by Fluka AG, Buchs, Switzerland, and by Tridom Chemical, Inc., Hauppauge, New York. The thiazolium salt may also be prepared as described below by benzylation of 5-(2-hydroxyethyl)-4-methyl-l,3-thiazole which is commercially available from E. Merck, Darmstadt, West Germany, and Columbia Organic Chemicals Co., Inc., Columbia, SC. The acetonitrile used by the checkers was dried over Linde 3A molecular sieves and distilled under nitrogen, bp 77-78°C. The same yield of thiazolium salt was obtained by the checkers when benzyl chloride and acetonitrile from commercial sources were used without purification. 

Materials and Polymerization. Styrene and methyl methacrylate were obtained from commercial sources and were distilled to remove inhibitor. After distillation, the monomers were stored, under nitrogen, in a refrigerator. For the mixed emulsifier system, Emulphogene BC840(GAF), tridecyloxy-polyethylene-oxyethanol, was used as the nonionic constituent, and sodium lauryl sulfate (K and K Labs) was used as the ionic constituent. The sodium lauryl sulfate was at a concentration below its cms whereas the BD-840 was at a concentration above its cmc. This emulsifier system has been shown to yield mixed micelles (2)/ having a low ionic change (2)/ which produce latlces with rather narrow particle size distributions (2 ) ... 

The four kinds of active carbons used in our laboratory were obtained from different commercial sources and in accordance with supplier information were produced from various precursors. Ash was removed from the raw carbon using concentrated hydrofluoric and hydrochloric acids by Korver s method [166]. Carbon samples were subjected to surface modification by oxidation in air or with concentrated HNO, annealing in a vacuum or an ammonia atmosphere. Afterwards, all carbon samples were desorbed under vacuum (10" Pa) at 150°C (423 K) for 3 h. The procedure used for carhon purification ensured the removal of nitric acid and nitrogen oxides (after nitric acid oxidative modification) or physically sorbed NHi (after heat treatment in ammonia). The samples thus prepared... 

All experiments have been performed under a dry nitrogen atmosphere by standard Schlenk techniques. Solvents have been purified by distillation over suitable drying agents and degassed prior to use. All other reagents (technical grade) have been purchased from commercial sources and used as received. 1H and 31P NMR chemical shifts are referenced with respect to external TMS and aqueous 85% H3PO4, respectively. 

Materials. The reagents Mo(CO)e, W(CO)6, iodine, tetrapropyl-ammonium bromide, tetrabutylammonium iodide, propionic acid, benzoic acid, pivalic acid, and 1,2-dibromoethane were obtained from commercial sources and used without purification. The solvents chlorobenzene, 1,2-dichloroethane, o-dichlorobenzene, toluene, decahydronaph-thalene (decalin), and cyclohexane were purged 10-30 min with a stream of dry nitrogen prior to use. Acetonitrile was dried over molecular sieves (4A) and also purged with nitrogen prior to use. Benzene used in the preparation of MoW(02CC( 113)3)41 was carefully dried and stored over calcium hydride, then vacuum distilled into the reaction vessel when needed. 

Materials. Tungsten hexacarbonyl, iodine, triphenylphosphine, CO gas, and sodium N,IV-dimethyldithiocarbamate were obtained from commercial sources and used without further purification. Solvents were purged with a stream of purified nitrogen prior to use. All solution manipulations were performed under a nitrogen atmosphere using Schlenk techniques. 

Although the ultimtite source of practically all nitrogen is probably the atmosphere, there are today four generally accepted commercial sources, viz., the organics, the deposits of natural nitrates, the deposits of coal and peat, and the atiiiusphere. 

Pyromellitic dianhydride (PMDA) was obtained from commercial sources and purified by vacuum sublimation, m.p. 285°. The m-phenylenediamine was recrystallised three times from dry benzene and dried at room temperature over CaCl at 2)mm. The monomer was further purified by sublimation, m.p. 59 . p-Phenylene diamine was siiblimed twice (80 /3mnO from activated charcoal and stored under nitrogen. Dimethyl formamide (DMF) (b.p. 79 /38mm) was distilled from calcium hydride and stored over molecular sieves. 

All of the aromatic ketones and silanes were used as purchased from commercial sources. Tetrahydrofuran (THE) was purified prior to use by first drying over calcium hydride, then fractionally distilling. Alternatively, THE was distilled under nitrogen from sodium naphthalene complex. N,N,N, N -Tetramethylurea (TMU) was dried over calcium hydride and then fractionally distilled, while hexamethylphosphoramide was used as purchased. Magnesium metal was used in the form of 30 mesh shot. 2,3,5,6-Tetrachloro-1,4-benzoquinone used in the kinetic studies was recrystallized from acetone prior to use. Toluene, p-xylene, and benzene were dried by refluxing over calcium hydride followed by fractional distillation. Octamethylcyclotetra-siloxane (D ) was dried and purified by distillation at atmospheric pressure. The first and last fractions were discarded and the center fraction, boiling at 175-176°C, was used. Karstedt s catalyst was obtained from General Electric Silicone Products Business Division.Eiltrol-20 was used as purchased from the Eiltrol Company. Styrene monomer was freed from... 

The EMA was obtained from a commercial source and purified by fractional distillation under nitrogen pressure. The monomer... 

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