Quartz vessels

By the direct union of hydrogen and chlorine. Very pure hydrogen chloride is made by direct union of pure hydrogen and chlorine in a quartz vessel. 

The photochemical addition of trifiuoroiodomethane to unsaturated systems has been thoroughly investigated by Haszeldine. Little use has been made of this reaction in the steroid field. Irradiation of the enol ether (64) in trifiuoroiodomethane containing pyridine in a quartz vessel furnishes in 60 %... 

Quarz-gang, m. quartz vein, -gefass, n. quartz vessel, -gerat, n. quartz apparatus, quartz ware, -glas, n. quartz glass, -gut, n. quartz ware. 

Phenyl-2-oxa-3-azabicyclo[3.2.0]hepta-3,6-diene (11 0.200 g, 1.17 mmol) in hexane was irradiated in a quartz vessel using a Rayonet photoreactor to give the product as a yellow oil yield 0.160 g (SO %). The compound can be distilled below 100 C at 10 4Torr. It gradually resinifies when kept in air at 20 C. 

Combustion of liquid sulfur, contained in a quartz vessel, in a stream of pure oxygen under reduced pressure (8 mbar, 800 Pa) produces a mixture of SO2, S2O, and little SO3 the latter and any sulfur vapor can be removed by a filter of glass wool [12]. The S2O content of the gas then reaches at most 32% and decreases with increasing pressure [13] ... 

Gas-phase reactions have been carried out in 160 mL quartz vessels, and the products analyzed online by mass spectrometry (Brubaker and Hites 1998). Hydroxyl radicals were produced by photolysis of ozone in the presence of water ... 

One disadvantage to using external light sources is that for irradiations using 2537-A light, a Pyrex reaction vessel cannot be used since Pyrex absorbs strongly at wavelengths less than 3000 A. Therefore more expensive quartz vessels must be used. 

MedChem Kit (Fig. 3.5) An accessory especially designed for medicinal chemistry laboratories to cover working volumes of 2-140 mL. The package contains a 12 mL glass vial, a 50 mL quartz vessel, and single-pressure reactor segments (100 mL and 270 mL, respectively). 

For the individual rotor types, different vessels are available. The 16-vessel rotor, dedicated for the performance of standard reactions at up to 240 °C, offers 100 mL PTFE-TFM liners. Applying different pressure jackets allows continuous operation of these vessels to a maximum of 20 or 40 bar, respectively. The 8-vessel rotor is designed for high-pressure reactions, offering PTFE-TFM liners or quartz vessels, which enable reactions to be performed at 300 °C and 80 bar for several hours. 

Fig. 4.4 Temperature and power profiles for a Biginelli condensation (Scheme 4.24.a) under sealed quartz vessel/microwave irradiation conditions (see Fig. 3.17). Linear heating ramp to 120 °C (3 min), temperature control using the feedback from the reference vessel temperature measurement (constant 120 °C, 20 min), and forced air cooling (20 min). The reaction was performed in eight quartz vessels...

Photooxidation of chlorobenzene in air containing nitric oxide in a Pyrex glass vessel and a quartz vessel gave 3-chloronitrobenzene, 2-chloro-6-nitrophenol, 2-chloro-4-nitrophenol, 4-chloro-2-nitro-phenol, 4-nitrophenol, 3-chloro-4-nitrophenol, 3-chloro-6-nitrophenol, and 3-chloro-2-nitrophenol (Kanno and Nojima, 1979). A carbon dioxide yield of 18.5% was achieved when chlorobenzene adsorbed on silica gel was irradiated with light (A. >290 nm) for 17 h. The sunlight irradiation of chlorobenzene (20 g) in a 100-mL borosilicate glass-stoppered Erlenmeyer flask for 28 d yielded 1,060 ppm monochlorobiphenyl (Uyeta et al., 1976). 

High Pressure Asher HPA (Pressure decomposition in quartz vessels) ... 

In the reaction between trifluoromethyl iodide and selenium at 265—290° bistrifluoromethyl selenide, (CF3)2Se, and bistrifluoromethyl diselenide, (CF3)2Sea, are produced in yields of 40 and 20% respectively (Table 4). These two compounds show a number of interesting reactions. The compound (CF3)2Se is converted quantitatively to CF3CI and, SeCl4 when irradiated in a quartz vessel with ultraviolet light. If the irradiation is done in Pyrex, however, a new solid compound CFjSeClg is formed, which hydrolyses to the crystalline acid CF3SeO(OH) (m.p. 118°). The... 

Torigoe and Esumi proposed silver(I) bis(oxalato)palladate(II) as a precursor of Ag/Pd bimetallic nanoparticles stabilized by PVP (45). Photoreduction of the aqueous precursor in a quartz vessel gave Ag/Pd bimetallic nanoparticles at various concentrations. The particles deviate from spherical ones but are uniform. Each particle contains both metal elements, as confirmed by EDX measurement. The size can be changed with concentration of the precursor. The average composition of... 

As a final example we would like to note the reactions of quinone methide 27, which remains unchanged upon irradiation in methanol solution through a Pyrex or Vycor filter.128 Reduction is observed when 27 is irradiated in isopropyl alcohol with benzophenone or acetophenone,129 in methanol with acetophenone, or in methanol with no sensitizer through quartz.128 While the effect of ketone sensitizers is due to chemical sensitization,129 the wavelength effect is much more surprising. Further investigation showed that irradiation of methanol alone in a quartz vessel yielded ethylene glycol. The 185 nm line of the mercury arc, which is absorbed by Vycor and Pyrex, decomposes... 

A pentane (450 mL) solution of 5.6-dimethylenebicyclo[2.2.1]heptan-2-one was degassed at 20 "C with dry N2 for 30 min. After cooling to — 30 C, the stirred solution was irradiated (253.7 nm, Hanau TNN 15/32) in a quartz vessel for 24 h. The slightly yellow solution contained starting material ( 28%), 2,3-dimethylenebicyclo[2.1.1]hexane (26%) and polymers (46%, partially precipitated at — 30 C). The solution was concentrated by distillation. The residue was combined with four other residues obtained under the same conditions. Distillation afforded the crude diene yield 490-500mg (36% based on reacted ketone) bp 80 C/2 Torr. The diene was purified by preparative GC (FFAP 10% or SE 30 10% on WAW Chromosorb, 60/80 mesh). 

Fourth, the present procedure bears a resemblance to the photochemical reaction of aryl iodides with trialkyl phosphites, by means of which several dialkyl arylphosphonates have been prepared.13 However, prolonged irradiation (>24 hours) in quartz vessels was employed. 

Silver bromide [7785-23-1] M 187.8, m 432 . Purified from Fe, Mn, Ni and Zn by zone melting in a quartz vessel under vacuum. 

SF4 (0.5 g, 5 mmol) was condensed into a 150-mL quartz vessel, followed by trifluoromethyl hypochlorite (1.2 g, 10 mmol). The mixture was allowed to warm to 25 °C and was photolyzed for 24 h with a Hanovia utility UV quartz lamp. After this period the remaining material was vacuum distilled and c -bis(trifluoro-methoxy)sulfur tetrafluoride was retained in a trap at — 78°C yield 90-95%. 

In a thoroughly dried 250-mL quartz vessel was placed phenylstibonic acid (1 0.75 g. 3 mmol) dissolved in anhyd CH2C12 (20mL). The vessel was cooled to — 70 C and evacuated, then SF4 gas (1 g, 10 mmol) was let in and the temperature was gradually raised to 20 C. The precipitated complex PhSbF4 SF4 was filtered with exclusion of moisture, washed with pentane, and heated in vacuo (1 Torr) for 6 h at 65-70 C yield of 2 0.72 g (86.5%) mp 125-126 C. 

Irradiation of thioglycolic acid and of dimethyl dithiodiglycollate in the presence of 3,4-benzpyrene (LII) with a mercury arc in quartz vessel, but not in a Pyrex vessel, produces 5-benzpyrenylacetic acid (LIII) and methyl 5-benzpyrenylacetate, respectively. The latter is also obtained on irradiation of 5-benzpyrenylmercaptoacetic acid (LIV).48... 

With toluene, in a Pyrex vessel, the products were ethylbenzene, m-and p-xylenes, and an unidentified product. In a quartz vessel o-xylene was also found and the unidentified product decreased, suggesting that the unidentified product was a methyl cycloheptatriene capable of undergoing photoisomerization to give xylenes. 

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