Pyrex 1 99 table

As was discussed above the necessary condition for Cerenkov-type phase-matched frequency-doubling is that the effective refractive index of the fundamental mode is smaller than the refractive index of the substrate at 2flX This condition can be fulfilled for DCANP deposited on pyrex. Table 1 lists the refractive indices at the fundamental and the second-harmonic wavelengths, the thicknesses t of the films used in our experiments and the calculated and measured Cerenkov angles. As can be seen from Table 1 the Cerenkov angles 0 co/c and Q meas are in agreement within the experimental errors. 

Because of the risk of lead poisoning, the exposure of children to lead-based paint is a significant public health concern. The first step in the quantitative analysis of lead in dried paint chips is to dissolve the sample. Corl evaluated several dissolution techniques. " In this study, samples of paint were collected and pulverized with a Pyrex mortar and pestle. Replicate portions of the powdered paint were then taken for analysis. Results for an unknown paint sample and for a standard reference material, in which dissolution was accomplished by a 4-6-h digestion with HNO3 on a hot plate, are shown in the following table. 

Table 18.8 Physical property data for used silica, crown glass and pyrex...

A 50 mL or 100 mL burette, with Pyrex glass-wool plug or sintered-glass disc at the lower end, can generally be used for the determinations described below alternatively, the column with side arm (Fig. 7.4a) is equally convenient in practice for student use. Reference will be made to the Duolite resins the equivalent Amberlite or other resin (see Table 7.1 in Section 7.1) may of course be used. 

Mix 400 mL of pure concentrated hydrochloric acid with 250-400 mL of distilled water so that the specific gravity of the resultant acid is 1.10 (test with a hydrometer). Insert a thermometer in the neck of a 1 L Pyrex distillation flask so that the bulb is just opposite the side tube, and attach a condenser to the side tube use an all-glass apparatus. Place 500 mL of the diluted acid in the flask, distil the liquid at a rate of about 3-4 mL min-1 and collect the distillate in a small Pyrex flask. From time to time pour the distillate into a 500 mL measuring cylinder. When 375 mL has been collected in the measuring cylinder, collect a further 50 mL in the small Pyrex flask watch the thermometer to see that the temperature remains constant. Remove the receiver and stopper it this contains the pure constant boiling point acid. Note the barometric pressure to the nearest millimetre at intervals during the distillation and take the mean value. Interpolate the concentration of the acid from Table 10.5. 

Details for the preparation of the solutions referred to in the table are as follows (note that concentrations are expressed in molalities) all reagents must be of the highest purity. Freshly distilled water protected from carbon dioxide during cooling, having a pH of 6.7-7.3, should be used, and is essential for basic standards. De-ionised water is also suitable. Standard buffer solutions may be stored in well-closed Pyrex or polythene bottles. If the formation of mould or sediment is visible the solution must be discarded. 

Figura 2.9 Dse of th Grob test Mixture to compare tbe activity of various glass surfaces coated with ov-ioi. Surface types A > Untreated pyrex glass, B pyrex glass deactivated by thermal degradation of Ceurbowax 20M, C < SCOT column, prepared with Silanox 101, D pyrex glass column coated with a layer of barium carbonate and deactivated as in (B), and E - untreated fused silica. Components are identified in Table 2.7 with ac - 2-ethylhexanoic acid. (Reproduced with permission from ref. 152. Copyright Elsevier Scientific Publishing Co.)...

The eutectics examined and their melting points are given in Table 3.1. The compounds were melted in 10 mm inner diameter pyrex tubes, and polished sections were prepared from the solidified eutectic samples. 

Table II Check on Reciprocity Law Induction Time for Cross-linking of Elvacite 2046 Under Various Intensities of Illumination In a Xenon-Arc Fade-ometer With Pyrex-Glass Filter...

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... 

In contrast to a straightforward and predictable decomposition pattern of photolysis with >400 nm light, irradiation of nitrosamides under nitrogen or helium with a Pyrex filter (>280 nm) is complicated by the formation of oxidized products derived from substrate and solvent, as shown in Table I, such as nitrates XXXIII-XXXV and nitro compound XXXVI, at the expense of the yields of C-nitroso compounds (19,20). Subsequently, it is established that secondary photoreactions occur in which the C-nitroso dimer XIX ( max 280-300 nm) is photolysed to give nitrate XXXIII and N-hexylacetamide in a 1 3 ratio (21). The stoichiometry indicates the disproportionation of C-nitroso monomer XVIII to the redox products. The reaction is believed to occur by a primary photodissociation of XVIII to the C-radical and nitric oxide followed by addition of two nitric oxides on XVIII and rearrangement-decomposition as shown below in analogy... 

The enthalpy of combustion of 1.00 mol CH3OH(l) is —726 kj. (a) Write a balanced equation for the combustion of 1 mol CH3OH(l). (b) What mass of methanol must be burned to heat 209 g of water in a 50.0-g Pyrex beaker from 20°C to 100°C For additional information, see Table 6.1. (c) Using the enthalpy of combustion and the enthalpies of formation of the products of the combustion reaction, calculate the enthalpy of formation of methanol. 

While we have not yet carried out detailed kinetic measurements on the rate of photocorrosion, our impression is that the process is relatively insensitive to the specific composition of the strontium titanate. Trace element compositions, obtained by spark-source mass spectrometry, are presented in Table I for the four boules of n-SrTi03 from which electrodes have been cut. Photocorrosion has been observed in samples from all four boules. In all cases, the electrodes were cut to a thickness of 1-2 mm using a diamond saw, reduced under H2 at 800-1000 C for up to 16 hours, polished with a diamond paste cloth, and etched with either hot concentrated nitric acid or hot aqua regia. Ohmic contacts were then made with gallium-indium eutectic alloy, and a wire was attached using electrically conductive silver epoxy prior to mounting the electrode on a Pyrex support tube with either epoxy cement or heat-shrinkable Teflon tubing. 

Alkylation of 1. To a mixture of the ester 1 (5 g, 25 mmol) and 6% of Aliquat 336 (715 mg, 1.5 mmol) was added t-BuOK (3.3 g, 25 mmol, 1 equiv.) under magnetic stilling over 15 min alkyl bromide (25 mmol, 1 equiv.) was then added slowly. The flask was left under the experimental conditions indicated in Table 1. Finally, the mixture was diluted with ethyl acetate (50 ml) and filtered on Florisil (10 g). The crude products were analysed by GC and characterised by MS and HNMR. 2-Alkylcyclohexanones. A mixture of lithium bromide (1.73 g, 20 mmol), tetrabutylammonium bromide (323 mg, 1 mmol), water (360 mm, 0.36 mL, 20 mmol) and ethyl l-alkyl-2-oxocyclohexanecarboxylate 2 (10 mmol) was placed in a Pyrex tube. The tube was then introduced into a Maxidigest MX 350 Prolabo microwave reactor fitted with a rotational system. Microwave irradiation was carried out for a suitable power and time (Table 2). An approximate final temperature was measured by introducing a digital thermometer at the end of irradiation. The mixture was cooled to ambient temperature. After elution with ethyl acetate (50 mL) and subsequent filtration on Florisil, organic products were analyzed by GC and finally purified by chromatography on silica gel (pentane-ethyl acetate, 95 5). 

All reactions were performed in a cylindrical Pyrex vessel using 10 mmol of nitrone 1 and 20 mmol of dipolarophiles 2 or 4. The mixtures were introduced into the monomode reactor (Maxidigest MX 350 Prolabo) at the powers and times indicated in Table 1. Temperatures were recorded throughout the reaction using an IR detector connected to the reactor. At the end of the reaction, after cooling down and extraction with CH2CI2, products 3, 5a and 5b were analyzed by GC methods using an internal standard and authentic samples. 

A mixture of eugenol 1 (15 mmol), crushed potassium hydroxide or terbutoxide (33 mmol), the phase transfer catalyst (0.75 mmol) was placed either in a beaker in a domestic oven or in a Pyrex tube introduced into the Maxidigest MX 350 Prolabo microwave reactor filled with a rotational system. Microwave irradiation was carried out in the conditions described in Table 3 and 4. The mixture was cooled to ambient temperature. After elution with diethyl ether (50 mL) and subsequent filtration on Florisil, the organic products were analyzed by GC using an internal standard and characterized by 1H NMR spectroscopy by comparison with authentic samples. 

In all examples discussed up to now the radical cation of Qo is involved in the reaction mechanism. However, due to the electronic features reduction of the fullerenes leading to radical anions should be much easier performed. For example, a useful method to synthesize 1-substituted l,2-dihydro-[60]fullerenes is the irradiation of Q0 with ketene silyl acetals (KAs) first reported by Nakamura et al. [216], Interestingly, when unstrained KAs are used, this reaction did not yield the expected [2 + 2]-cycloaddition product either by the thermal, as observed by the use of highly strained ketene silyl acetals [217], or by the photochemical pathway. In a typical reaction Q0 was irradiated for 10 h at 5°C with a high pressure mercury lamp (Pyrex filter) in a degassed toluene solution with an excess amount of the KA in the presence of water (Scheme 11). Some examples of the addition of KAs are summarized in Table 11. 

Anodic bonding of Si to Pyrex was commonly used to create a sealed Si chip [1,281,442,820,836]. Various bonding conditions used are summarized in Table 2.2. A positive voltage is applied on the Si wafer with respect to that of the Pyrex wafer (negative) [91,92,281]. 

As mentioned above, small-scale photoreactions are quite often carried out in quartz or Pyrex tubes, by external irradiation. However, this is certainly not an optimal solution for maximizing the exploitation of the emitted radiation. Internal irradiation is obviously better from the geometric point of view, but (relatively) large-scale preparations must take into account all of these factors and achieve optimal light and mass transfer. These elements are not taken into account in exploratory studies or small-scale syntheses, just as is the case for thermal reactions, where the optimization is considered at a later stage the essential requirement is that the explorative study is carried out under conditions where occurrence of the reaction is not prevented. Thus, it is important that the source is matched with the reagent absorption, the vessel is of the correct material, and the solvent does not absorb competitively (unless it acts also as the sensitizer). Figure 1.7 and Table 1.1 may help in this choice, in conjunction with the U V spectra of all of the compounds used (it is recommended that the spectra are measured on the actual samples used, in comparison with those taken from the literature, in order to check for absorption by impurities). 

This equation is a powerful tool for the description of the adsorption data in microporous material. In Figure 6.11, the Dubinin plot of the adsorption isotherm in the range 0.001 < P/P0 < 0.03, describing the adsorption of NH3 at 300 K in the natural clinoptilolite sample HC is shown (see Table 4.1) [25], The adsorption data reported in Figure 6.11 were determined volumetrically in a home-made Pyrex glass vacuum system, consisting of a sample holder, a dead volume, a dose volume, a U-tube manometer, and a thermostat [25,31], It is evident that, in the present case, the experimental data is accurately fitted by Equation 6.20. 

In Figure 6.12 [2,25], the plot of the linear form of the osmotic isotherm equation, with B = 0.5, using adsorption data of NH3 adsorbed at 300 K in an homoionic magnesium natural zeolite sample labeled CMT (see Table 4.1), is shown. The adsorption data reported in Figure 6.12 were determined volumetrically in a Pyrex glass vacuum system, previously described in the case of the Dubinin equation [25,31], With this plot, it is possible to calculate the maximum adsorption capacity of this zeolite, which is m = Na = 5.07mmol/g and b = UK = -0.92 (Torr)05. 

Fig. 25. Kinetics for the recombination of H atoms by Pyrex and quartz. Experimental points o, Wood and Wise [91] A,Tsu and Boudart [64a] , Smith [54], Theoretical lines [(Ng) = 1014cm 3] —, Wood and Wise [91] calculated for the model of de Boer and van Steenis [98] (see Table 8 for values of the energy parameters).

Reagent grade potassium chloride is intimately mixed with reagent grade metal-(II) chloride and the mixture is heated in a 250-mL pyrex beaker, in air at 200-250° for 3 hours. Proportions of mixed salts and compositions of the different double chlorides appear in Table II. 

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