Barium complexes pyridine oxide

Purex process, 6,940 Barium, pentakis(diacetamide)-stereochemistry, 1, 99 Barium alkoxides synthesis, 2,336 Barium complexes cryptands, 3,53 phthalocyanines, 2, 863 porphyrins, 2,820 pyridine oxide, 3,9 urea, 3,9... 

Barium complexes cryptands, 53 pyridine oxide, 9 urea,9 Beauveracin... 

All reactions and sample preparations are carried out in an inert-atmosphere enclosure under dry nitrogen. Solvents and reagents are dried in the following manner. Benzene, tetrahydrofuran, and n-pentane are freshly distilled from lithium aluminum hydride pyridine is distilled over barium oxide and tetramethylethylenediamine is distilled over calcium hydride. Solvents used in preparing nmr and infrared samples are degassed by a freeze-thaw technique. Nmr spectra are obtained with torch-sealed nmr tubes. The commercial transition metal carbonyl complexes are recrystallized and vacuum-dried before use. Glassware is routinely flame-dried. 

Caprolactone (CL) (Acros, 99%) was dried over calcium hydride at r.t. for 48h and then distilled under reduced pressure. 2-(N,N-dimethylamino)ethyl methaciylate (DMAEMA) (Aldrich, 98%) was deprived of its inhibitor by filtration through a basic alumina column, and depending on samples (see text) dried over calcium hydride at r.t. for 24h and then distilled under reduced pressme. Butane-1,4-diol (Acros, > 99%) was dried over calcium hydride for 48h at r.t. and distilled at 70°C under reduced pressure. Triethylamine (NEts, Fluka, 99%) was dried over barium oxide for 48h at r.t. and distilled under reduced pressure. Copper bromide (CuBr, Fluka, 98%) was purified in acetic acid and recrystallized in ethanol under inert atmosphere until a white powder is obtained. Tin(ll) bis-2-ethyl hexanoate (Sn(Oct)2, Aldrich, 95%), methacrylic anhydride (Aldrich, 94%), N,N-dimethylamino-4-pyridine (DMAP, Acros 99%), 1,1,4,7,10,10-hexamethyltriethylene tetramine (HMTETA, Aldrich, 97%), ethyl-2-bromoisobutyrate (E BBr, Aldrich, 98%), N,N-dicyclohexylcarbodiimide (DCC, Acros, 99%), were used as received. Tetrahydrofuran (THF, Labscan, 99%) was dried over molecular sieves (4A) and distilled over polystyryl lithium (PS LC) complex under reduced pressure just before use. Toluene (Labscan, 99%) was dried by refluxing over CaH2. 

Perchlorates are powerful oxidizing substances. These compounds explode when mixed with combustible, organic, or other easily oxidizable compounds and subjected to heat or friction. Perchlorates explode violently at ambient temperatures when mixed with mineral acids, finely divided metals, phosphorus, trimethylphosphite, ammonia, or ethylenediamine. Explosions may occur when perchlorates are mixed with sulfur, or hydride of calcium, strontium, or barium and are subjected to impact or ground in a mortar. Perchlorates react with fluorine to form fluorine perchlorate, an unstable gas that explodes spontaneously. Heating perchlorates to about 200°C (392°F) with charcoal or hydrocarbons can produce violent explosions. Metal perchlorates from complexes with many organic solvents, which include benzene, toluene, xylenes, aniline, diozane, pyridine, and acetonitrile. These complexes are unstable and explode when dry. Many metal perchlorates explode spontaneously when recrystaUized from ethanol. Saturated solution of lead perchlorate in mathanol is shock sensitive. 

The organic adsorbate in a small vessel was put into a phosphorous oxide desiccator and its vapor was allowed to adsorb on the clay at room temperature. When the adsorbate was solid, a clay sample was Immersed into the cyclohexane solution and dried in the desiccator. In the adsorption of pyridine, barium oxide was used as a drying agent. The formation rate of colored complexes was dependent on the adsorbate molecules and the dryness of montmorillonite. In the case of anisole or phenol, the color began to appear at once when the adsorbate was brought into contact with the dried montmorillonite, but it took about two weeks to finish the reaction in pyridine adsorption. 

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