Borosilicate glass reaction with

Glass reactors Many studies have been carried out in borosilicate glass reactors similar to those used in typical laboratory studies of gas-phase reactions. These are usually relatively small, a few liters up to approximately 100 L (0.1 m3). However, Doussin et al. (1997) have developed a borosilicate glass chamber with a volume of 977 L by using four cylinders held together by flanges. 

Haswell and coworkers carried out the Wittig reaction of 2-nitrobenzyl triphenylpho-sphonium bromide with methyl 4-formylbenzoate in a microflow system [17,18]. They used a borosilicate glass microreactor with T-shaped channels (width = 200 pm and depth = 100 pm), and the reagents were added via EOF by applying a constant... 

Chemical Reactions. Products from gas-phase chemical reactions can also be trapped in rare gas matrices, and those products which absorb light can be studied by optical spectroscopic techniques. For example (31), the products from a low pressure 1 mm. of Hg) atomic flame of oxygen atoms plus acetylene were allowed to leak through a small oriflce in a borosilicate glass reaction chamber, where they were mixed with an excess of gaseous krypton at 1(H mm. of Hg pressure. The mixture was condensed on a quartz window cooled to liquid helium temperature. The only detectable small free radical found was HCO, but it was present in considerable quantities. Similar experiments by Harvey and Brown (23) showed that HNO could be easily produced and trapped from the gas-phase reaction of hydrogen atoms plus nitric oxide. 

A. TMT. Temperature of reaction vessel, 195° to 300° C. Borosilicate glass reaction vessel, the surface-volume ratio of which could be altered by a factor of up to 7.5 by packing with either borosilicate glass or silica glass wool. Reaction time, 0.7 to 3.0 seconds. Total pressure in reaction vessel 4 to 10 mm. Carrier gases, nitrogen, carbon dioxide, sulfur hexafluoride, and cai bon dioxide-nitric oxide. 

Quantitative Data. Results. Four initial experiments were carried out at temperatures close to 100° C. in two different reaction vessels. Two of the experiments, one with about 500 mm. of mercury of oxygen added initially, were carried out in a 537-cc. borosilicate glass sphere and the other two in an irregularly shaped, 461-cc. borosilicate glass vessel with about 45% greater surface. 

Irradiation Procedure. Reaction mixtures were prepared at room temperature by transferring desired quantities of reactants from their storage bulbs to the reaction vessel, a 500-cc. spherical borosilicate glass flask attached to the vacuum line by a section of glass capillary tubing and a 4-mm. bore threaded glass valve with a Teflon plug (Fischer and Porter 795-609). Prior to each experiment this vessel was baked under vacuum at 500°C. for 12 or more hours. 

Photolytlc. The sunlight irradiation of 1,3,5-trichlorobenzene (20 g) in a 100-mL borosilicate glass-stoppered Erlenmeyer flask for 56 d yielded 160 ppm pentachlorobiphenyl (Uyeta et al, 1976), A photooxidation half-life of 6.17 months was reported for the vapor-phase reaction of 1,3,5-trichlorobenzene with OH radicals (Atkinson, 1985). 

WUes and Watts [48,53] have reported the use of a rather successful heterogenic catalytic system to carry out these reactions. They have tested a borosilicate glass microreactor (dimensions 3.0 x 3.0 x 0.6 cm) consisting of two etched layers with two inlets, mixing channels, a larger etched region and the outlet. A solid-supported catalyst was dry-packed in this structure (Fig. 4). 

Fig. 3.25. The Pask-Nuyken device for measuring simultaneously the conductivity and the UV spectrum of a reaction mixture. A mixing chamber, B conductivity cell with jacket, C graded-seal borosilicate glass-soda glass, D jacketed quartz cell, E copper leads to platinum electrodes Pt, F graded-seal borosilicate glass-quartz.

Gas-phase experiments at 155 °C. were carried out in a 250-ml. cylindrical Vycor reactor in a hot-air furnace. Later experiments were done in a 500-ml. borosilicate glass flask heated in an oil bath. With either system, di-terf-butyl peroxide, oxygen, and isobutane were metered into the reaction vessel in that order by expansion from the vacuum line the pressure of each component was measured using a mercury or oil manometer. Mercury vapor was excluded from the reaction vessel. 

A complete methodology for the manipulation and reaction of air-sensitive solutions has evolved around cappable glass pressure bottles. Soft-drink bottles are sometimes used (hence these procedures are sometimes referred to as pop bottle techniques ) however, heavy-walled borosilicate glass pressure reaction vessels are superior. In contrast to the modified standard taper ware discussed above, this pressure apparatus offers advantages where modest pressures are necessary and where the centrifugation of precipitates is preferable to filtration. These techniques are especially popular in the preparative-scale study of catalytic reactions of small molecules, such as olefin polymerization. The pressure bottle is fitted with a cap containing two 1/8 in. holes and a rubber liner, which is secured by means of a hand-operated bottle capper (Fig. 1.31).18... 

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