Glasses sealing glasses

Another set of apparatus ( B) adopts the 5 19 joint as standard (apart from 7/12 for thermometers) but connexions to condensers, etc., incorporate internal glass seals. A typical assembly for distillation is depicted in Fig. XII,... 

The samples were collected and processed in a manner to avoid exposure to oxygen and control loss of moisture then they were pulverized to convenient sizes for research, ie, <149 fim ( — 100 mesh) and <840 fim (—20 mesh) the entire ton was thoroughly mixed and packaged in sealed glass ampules under nitrogen. These samples have been well characterized and are available in quantities that are expected to last for decades (Table 8). 

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.]... 

Treatment of resin-bound iminophosphorane 197 with an excess of solid CO2 and CS2 in a sealed glass tube, and with aryl isocyanates afforded I-OXO-, 1-thioxo- 198, and l-arylimino-l//-pyrido[l,2-c]pyrimidine-3-car-boxylates 199 (OlJMClOll). Reaction of iminophosphorane 200, derived from 2-(2-azidophenyl)pyridine with excess PPh3, yielded 6//-pyrido[l,2-c] quinazoline-6-thione (201). 

Oxygen-sensitive substances. Substances that are moderately sensitive to oxygen (such as crystalline coelenterazine and Cypridina luciferin) can be stored aerobically at below — 70°C in a desiccated container for many years. They can be permanently stored in an evacuated fuse-sealed glass container even at room temperature, in darkness (for the technique, see Method II below). 

Fig. A.2. The sequence of making a sealed glass tube, from top to bottom.

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