Sealed glass ampoules

Butyryi chloride (butanoyl chloride) [141-75-3] M 106.6, f -89°, b 101-102°/atm, 1.026, Hp 1.412. Check IR to see if there is a significant peak at 3000-3500 cm (br) for OH. If OH is present then reflux with less than one mol equiv of SOCI2 for Ih and distil directly. The fraction boiling between 85-100° is then refractionated at atm pressure. Keep all apparatus free from moisture and store the product in sealed glass ampoules under N2. LACHRYMATORY - handle in a good fume hood. [Org Synth Coll Vol I 147 794/.]... 

Dissolve in Et20, add quinol (500mg for 300mL), dry over Na2S04, filter, evaporate and distil under dry N2. It is a clear liquid if dry and decompose very slowly. In the presence of H2O traces of tributyl tin hydroxide are formed in a few days. Store in sealed glass ampoules in small aliquots. It is estimated by reaction with aq NaOH when H2 is liberated. CARE stored samples may be under pressure due to liberated H2. [J Appl Chem 7 366 1957.]... 

Ring-opening polymerization was used to synthesize PTMC. The polymerization was carried out in evacuated and sealed glass ampoules with stannous octoate as a catalyst. The schematic reaction equations are shown in Schemes 8.7 and 8.8. The reaction time for aU homo- and copolymerizations were three days and the reaction temperature at 130 2°C. The obtained polymers were purified by dissolution in chloroform and precipitation in isopropanol. The precipitated polymers were collected, and washed with fresh isopropanol, and dried under reduced pressure at room temperamre until constant weight. 

Dining preparation of tungsten(IV) dibromide oxide, appropriate proportions of reactants are heated in an evacuated sealed glass ampoule to 400-500°C. Initially only one end should be heated to prevent excessive pressure bursting the ampoule. See other GLASS INCIDENTS See other halogens, oxidants... 

Besides the oxide sulfate described above, (NH4)2[Pt2(S04)4(H20)2] is obtained in the reaction of Pt(N03)2 with concentrated sulfuric acid in sealed glass ampoules at 400 °C.124 In the crystal structure, Pt2 dumbbells are coordinated by four bidentate-bridging sulfate ions and two axial H20 molecules. The... 

Solid samples can be introduced as a solution or in a sealed glass ampoule which is crushed in the gas stream by means of a gas-tight plunger. Only solids which have appreciable vapour pressures at the operating temperature of the column can be successfully chromatographed. 

Certain equipment configurations allow for the use of Dewar flask testing at elevated pressures. Several arrangements have proved successful such as a sealed glass ampoule in the Dewar flask, a steel pressure vessel in the flask, a Dewar flask in an autoclave under inert gas pressure, and a stainless steel Dewar flask. Dewar flasks provided with an addition line can also be used to study chemical reactions. In Figure 2.21, typical temperature-time curves of Dewar flask experiments are shown. 

More importantly, the P-bromophosphinimines react smoothly with CF3CH2OH in the presence of Et3N to form P-(trifluoroethoxy)phosphinimines (eq 4) ( ). On heating in either sealed glass ampoules or a stainless... 

In the solvent swelling study each coal was soaked In excess deuterated pyridine In a sealed glass ampoule for approximately two months before NMR measurements were made at room temperature. 

The formation of Jt-sulfur from Sg at 120 °C is a relatively slow reaction. Figure 11 shows how the concentration in freshly molten Sg increases with time. The half-life of this reaction at 120 °C amounts to about 180 min When Sg is dissolved in CSj and heated to 130-150 °C in a sealed glass ampoule,... 

Polymerization was carried out in a sealed glass ampoule and terminated by the addition of a small amount of methanol. The reaction mixture was poured into a large amount of methanol to precipitate the polymer formed. After standing it overnight the precipitate was collected by filtration, washed with methanol and dried in vacuo at 60eC. The combined filtrates were evaporated to dryness under reduced pressure and the residue was redissolved in benzene to remove a small amount of insoluble material. The methanol-soluble oligomer was freeze-dried from the benzene solution. 

Formal Stability Studies — Long-term and accelerated (and intermediate) studies undertaken on primary or commitment batches according to a prescribed stability protocol to establish or confirm the retest period of a drug substance or the shelf life of a drug product. Impermeable Containers — Containers that provide a permanent barrier to the passage of gases or solvents (e.g., sealed aluminum tubes for semisolids, sealed glass ampoules for solutions). 

Assay. Using a sample of 0.50—0.60g in a sealed glass ampoule, det the content of UDMH. by titration with std 0.1M. K iodate soln [prepd by dissolving 21.402g of K io-date (dried at 180°C) in distilled water and diluting to 1000ml in a volumetric flask]. 

A newer technique which shows promise but has not yet been fully tested is based upon the preparation and separation of aldonitrile acetates of reducing sugars (Equation 9.12). The dried sugar is dissolved in pyridine and treated with hydroxylamine hydrochloride in a sealed glass ampoule at 90°C for 0.5 hr. The mixture is cooled, acetic anhydride added, and another 30-min reaction is carried out in the resealed ampoule. Actual formation of the nitrile may occur in the injector of the gas chromatograph. Nonreducing sugars apparently do not form the nitrile but are present as the... 

Hewitt found that volatile organic compounds are readily lost from soil samples unless care is taken to limit surface area exposure and to ensure subsample isolation [338]. Volatile organic carbon losses were found to be most abundant during field collection and storage. Hewitt reported that fortified soils held in sealed glass ampoules at 4 °C, or dispersed in methanol and held at 22 °C, showed no significant losses over 20 and 98 days, respectively [339]. 

Gd Cg2 was generated by arc discharge using a Gd-graphite rod and isolated by a multistage HPLC technique SWCNT bundles were prepared by pulsed-laser evaporation. The doping of Gd C82 into the inner hollow space of SWCNTs was carried out in a sealed glass ampoule at 500 °C for 24 h. Prior to the introduction of SWCNTs to the ampoule, the SWCNTs were heated in dry air at 420 °C for 20 min [267]. 

The Ni-Bi couples were annealed in sealed glass ampoules, filled with high-purity helium (0.25 atm), at 150, 200 and 250°C for 1 to 300 h. Each couple was annealed successively a few times. After each anneal, the specimen surface was examined in the as-received conditions and after mechanical and/or electrolytic polishing. 

Test for improperly sealed glass ampoules by immersing in ethanolic methylene blue solution. The dye will penetrate those ampoules which are improperly sealed. 

A review of this field has been given by Haw (1999). Reactions can be followed either in sealed glass ampoules or flow-through cells constructed within the spectrometer. The formation of intermediates can be studied in real time. An elegant example of this was shown in an early study of methanol to gasoline conversion over HZSM-5 zeolites. As a result of the shape selectivity of the catalyst, spectroscopic evidence of reaction intermediates, which were not seen as reaction products, was observed (Anderson and Klinowski, 1990). 

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