Quartz-glass reactor

Iodosyltoluene (1.2 g, 4.7 mmol) was suspended in CH2C12 (20 mL) in a quartz glass reactor, cooled to — 20 C and then gaseous SF4 was introduced while stirring. The reaction was complete when all the solid material was dissolved (10 min). The solution was purged with dry N2 and the solvent was distilled off yield 100% mp 108 109 C. 

Catalytic activities and selectivities were determined separatdy in a fixed-bed U-tube quartz-glass reactor (8 mm i. d.) under similar conditions. Toluene conversion and benzonitrile formation were followed by on-line GC using a FID detector. The carbon oxides were measured by non dispersive infi-ared photometry. 

Reaction kinetics and product distribution were observed in a small isothermal quartz glass reactor (diameter 8mm) with plug flow characteristics (Fig. 1). 

Figure 15. View of the 6 m long quartz glass reactor of 1080 1 volume.

Table 2. Photolysis rates and the steady-state OH radical concentration estimated during the photolysis of all four i-methyl-2-nitrophenoIs (/ = 3, 4, 5, 6) investigated, (a) values for the photolysis rate obtained in the 1080 L quartz glass reactor.

Under Romanian-German-Spanish collaboration, experimental investigations of the gas-phase reactions of the NO3 radical with a series of benzenediol compounds were performed. The experiments were carried out in two chamber systems with in situ FT-IR (Fourier Transform -Infrared Spectroscopy) detection of reactants a 1080 1 quartz glass reactor at the Bergische University Wuppertal and in the EUPHORE outdoor smog chamber facility in Valencia/Spain. The kinetics of the reaction of NO3 radicals with three benzenediols using a relative kinetic technique have been investigated. 

The catalytic properties of the above mentioned samples were determined using a fixed bed U-tube quartz-glass reactor. The catalysts were applied as split (1-1.25 mm, 1.5 ml each). The following reaction conditions were performed molar ratio of toluene air ammonia water vapoim = 1 30 5 25, WIF = ca. 10 ghmol and atmospheric pressure. The reactor outlet flow was analyzed by on-line GC. 

The reactions were carried out in a continuous-flow reactor at atmospheric pressure. The catalyst (5 ml) was packed in a quartz glass reactor tube (12 mm diameter). Catalyst tests were carried out between 200°C and 500 °C, preferably at 300 °C. The feed of 2,2-dimethyl-1,3-propanediol was 1 g/h, in a stream of nitrogen (40 ml/min). The contact time was around 1 second. The liquid products were condensed in a water cooled trap, the volatile products were collected in a second, dry ice cooled trap and analyzed by glc. 

Temperature-programmed desorption (TPD) and surface reaction (TPSR) were carried out at 450 torr with a temperature increment of 15 K.min. A 598S GC-MS mass spectrometer was used for detection of the desorbed species. The sample was calcinated in a quartz glass reactor at 823 K in a He stream for 1 hour, cooled to 423 K and ethylbenzene was adsorbed. After evacuation at 423 K for 30 rain the sample was cooled to 300 K and TPD/TPSR started. 

The catalytic properties of the synthesised solids were determined during the partial oxidation of toluene (TO) to benzaldehyde (BA), p-methoxytoluene (MTO) to p-methoxybenzaldehyde (MBA, anisaldehyde) and p-chlorotoluene (CTO) to p-chlorobenzaldehyde (CBA). A microreactor set-up that contains a metering system for liquids and gases and a fixed bed quartz-glass reactor was used. The catalysts were introduced into the reactor as sieve fractions (1-1.25 mm) and mixed prior to oxidation runs with the equal portion of quartz glass (1 mm) to avoid local overheating. The product stream was analysed by on line-GC or it was trapped in aqueous ethanol and determined by off line-capillary GC. The formation of carbon oxides was continuously followed by non-dispersive IR photometry. 

Figure 3. Experimental setup with muffle furnace, quartz glass reactor, video system and online gas-analysers. Plots show change in diameter during conversion of a 2.47 mm droplet at 900° C in 3% oxygen. Comparison of experimental data (left) and modelling results (right) (Mueller et al., 2002b).

The multiwalled nanotubes as well as the herringbone type carbon nanofibers were synthesized in-house in a quartz glass fluidized bed reactor via chemical vapor deposition (CVD). The method is described in detail elsewhere.19 The platelet nanofibers, in contrast, were purchased from the company FutureCarbon GmbH (Bayreuth, Germany). 

Reactor (Quartz) glass stainless steel (No. 1.4435 or 1.4404) PVC (polyvinylchloride) ... 

For both type of microwave reactors, if the reactor is not supplied with a temperature sensor or more likely accurate temperature measurment is prerequisited during an experiment, the fiber-optic temperature sensor is directly applied to the reaction mixture. In order to secure the sensor from harsh chemicals, the sensor is inserted into a capillary that in turn is inserted into the reaction mixture. In such a case, it is strongly advocated to use capillaries that are made of quartz glass and are transparent to microwave irradiation. Any capillary that is made of glass or even borosilicate glass can always slightly absorb microwave energy, in particular, while the reaction mixture does not absorb microwaves efficiently, and in turn lead to failures of fiber-optic thermometer performance. 

Figure 2.29 Photograph of the ceramic reactor housing and the quartz-glass tubulare microreactor (visible through the center hole) [59].

Catalytic Hydrogen Combustion 2 [CHC 2] Quartz-glass Micro Reactor for Catalytic Hydrogen Combustion... 

Later, Veser [59] performed the reaction in a quartz-glass micro reactor with a diameter of 600 pm and 20 mm length (Figure 2.29). The ceramic housing of the reactor and the reactor itself were stable for temperatures exceeding 1100 °C. Again, a Pt wire of 150 pm diameter was used as a catalyst and electrically heated for startup. Residence times down to 50 ps could be achieved. 

H2S has previously been shown to adsorb on the glass reactor and ancillary equipment (1). To avoid errors resulting from this, a very small amount of H2S in N2 (500 ppm at 0.51/min) is added to the N2 reactor flow of 1.50-1.80 1/min for one to two hours prior to the actual pyrolysis experiment to allow the quartz reactor and the glass traps to equilibrate with the H2S. GC analysis of the reactor effluent with the H2S indicated the preferential adsorption of the H2S on the reactor system. Similar analysis of the effluent after the H2S conditioning was turned off did not show any H2S desorption. 

A xenon lamp was used as light source that irradiated the thin falling films flowing through a quartz glass window in the reactor [317]. Thiourea in methanol was used to reduce the labile endoperoxide directly to the stable diol product. The yield of cis-2-... 

Figure 10 shows schematic drawing of the novel bench-scale reactor system based on hollow tubes. The reactor (MTR) consists of a cylindrical vessel of diameter 0.056 m within which 54 hollow quartz glass tubes of diameter 0.006 m coated on its peripheral surface with catalyst were placed. The tubes were held securely within the reactor by two teflon end plates on which... 

Photolysis is conducted in a Rayonet photochemical reactor consisting of 16 tabular UV lamps mounted around the inner surface of a polished cylindrical reflector, air cooled by a fan. The vessel to be irradiated (Vycor 7912 or quartz glass) is suspended in the center of the cylinder along its axis. Low pressure mercury lamps are used, 84% of whose emission (12,800 w/ cm2) is of 2537 A. For irradiation below r.t. the reaction vessel is immersed in a cooling bath and a low pressure mercury lamp (Westinghouse G 10T5 1/2 H) is placed in a vacuum-jacketed well in the center of the vessel. 

Further details of the experimental set-up has been given earlier [5,6] Initially the experiments were carried out using a stainless steel reactor. This reactor (10 mm internal diameter) was not well suited for catalyst loadings below 100 mg. We have therefore constructed an additional much smaller reactor (3 mm dlam) made of quartz glass. It will fimctlon well down to 10-20 mg catalyst loading. Due to the high price of the C enriched methanol this reduction in catalyst quantity Is Important when a high space velocity is wanted. 

The reactor has two reaction zones and is made of a stainless steel vessel with five access ports two vertical access ports which are used for the introduction of reactant gases and the collection of powders, one horizontal access port which is composed of GaAs lens and water-cooled copper block, items 4 and 16 of Figure 3.28, allowing passage of the laser beam, and the remaining two accesses with quartz glass windows to monitor the reaction zones. A stainless steel plate with a suitable hole is placed between two reaction zones to minimise their interaction. 

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