As seals

Boron trichloride, BCI3. Colourless mobile liquid, m.p. — 107°C, b.p. 12-5°C. Obtained directly from the elements or by heating B2O3 with pels in a sealed tube. The product may be purified by distillation in vacuo. It is extremely readily hydrolysed by water to boric acid. TetrachJoroborates containing the BCJ4 " ion are prepared by addition of BCI3 to metal chlorides. 

Formed commercially by the polymerization of S, NajCOj and PhX in a sealed container at 275--370 C, substituted derivatives are known but not fully evaluated. Used as high-temperature adhesives, for laminates and in coatings. 

Even if all of the elements described so far have been present within a sedimentary basin an accumulation will not necessarily be encountered. One of the crucial questions in prospect evaluation is about the timing of events. The deformation of strata into a suitable trap has to precede the maturation and migration of petroleum. The reservoir seal must have been intact throughout geologic time. If a leak occurred sometime in the past, the exploration well will only encounter small amounts of residual hydrocarbons. Conversely, a seal such as a fault may have developed early on in the field s history and prevented the migration of hydrocarbons into the structure. 

Diagenetic Healing late precipitation of minerals on or near the fault plane has created a sealing surface (see diagenesis for more detail). 

Cataclasis the fault movement has destroyed the rock matrix close to the fault plane. Individual quartz grains have been ground up creating a seal comprising of rock flour . 

In abnormally pressured reservoirs, the continuous pressure-depth relationship is interrupted by a sealing layer, below which the pressure changes. If the pressure below the seal is higher than the normal (or hydrostatic) pressure the reservoir is termed overpressured. Extrapolation of the fluid gradient in the overpressured reservoir back to the surface datum would show a pressure greater than one atmosphere. The actual value by which the extrapolated pressure exceeds one atmosphere defines the level of overpressure in the reservoir. Similarly, an underpressured reservoir shows an pressure less than one atmosphere when extrapolated back to the surface datum. 

In order to contain normal or abnormal pressures, a pressure seal must be present. In hydrocarbon reservoirs, there is by definition a seal at the crest of the accumulation, and the potential for abnormal pressure regimes therefore exists. 

While with-in the mobile x-ray system, the waste in the sampler, is contained within a replaceable (and disposable) polyvinyl chloride (PVC) sleeve with a wall thickness of approximately 0.2-inches and a sealed bottom. It was anticipated that the PVC tube or sleeve would, with use, become highly contaminated with waste residues which drip of fall-off the sampler. The sleeve is coated with a conductive coating to prevent static electricity buildup . There are no sources of ignition in this sealed spare. The sampler (and waste) is coupling which includes a positive pressure gasket. This barrier is further isolated by a second barrier consisting of an epoxy coated aluminum sleeve also sealed-off from the main x-ray cabinet and PVC sleeve. There are also no potential sources of ignition in this isolated secondary space as well. 

Figure A2.5.31. Calculated TIT, 0 2 phase diagram in the vicmity of the tricritical point for binary mixtures of ethane n = 2) witii a higher hydrocarbon of contmuous n. The system is in a sealed tube at fixed tricritical density and composition. The tricritical point is at the confluence of the four lines. Because of the fixing of the density and the composition, the system does not pass tiirough critical end points if the critical end-point lines were shown, the three-phase region would be larger. An experiment increasing the temperature in a closed tube would be represented by a vertical line on this diagram. Reproduced from [40], figure 8, by pennission of the American Institute of Physics.

Although in teraetion s between vicinal I 4 atom s arc n om in ally treated as non bonded interactions, triost of the force fields treat these somewhat differently from normal 1 5 and greater non-bonded interactions. HyperCbern allows each of these 1 4 non-bonded interactions to be scaled down by a scale factor < 1.0 with AMBHR or OPI-S. bor HIO+ the electrostatic may be scaled and different param eters rn ay be ti sed for I 4 van dcr Waals interactions, fh e. AMBHR force field, for exam pie, n orrn a lly uses a seal in g factor of 0.5 for both van der Waals an d electrostatic interactions. 

Principle. A known weight of the substance is heated with fuming nitric acid and silver nitrate in a sealed tube. The organic material is thus oxidised to carbon dioxide and water, whilst the halogen is converted quantitatively into the corresponding silver halide. The latter js subsequently washed out of the tube, filtered and weighed. 

Principle. This is essentially a small-scale modification of the macro piethod described on p. 416, the substance being completely oxidised in a sealed tube with fuming nitric acid in the presence of silver nitrate, the halogen being thus converted into silver halide. The collection and weighing of the silver halide require special techniques on the semi-micro scale. 

The only disadvantage is that the procedure does not give accurate results if the compound sublimes the capillary tube method should be used in such cases, and it may be necessary to employ a sealed capillary tube. This apparatus should find a place in every laboratory. It is... 

The chief disadvantages of a Buchner funnel for filtration are (i) it is impossible to see whether the underside of the perforated plate is perfectly clean, and (ii) the larger sizes are top heavy. The first drawback is absent in the Jena slit-sieve funnel (Fig. 11,1, 7,/) this is an all-glass funnel provided with a sealed-in transparent plate, perforated by a series of angular slots, upon which the filter paper rests. The sintered glass... 

In a 500 ml. three-necked flask, equipped with a thermometer, a sealed Hershberg stirrer and a reflux condenser, place 32-5 g. of phosphoric oxide and add 115-5 g. (67-5 ml.) of 85 per cent, orthophosphoric acid (1). When the stirred mixture has cooled to room temperature, introduce 166 g. of potassium iodide and 22-5 g. of redistilled 1 4-butanediol (b.p. 228-230° or 133-135°/18 mm.). Heat the mixture with stirring at 100-120° for 4 hours. Cool the stirred mixture to room temperature and add 75 ml. of water and 125 ml. of ether. Separate the ethereal layer, decolourise it by shaking with 25 ml. of 10 per cent, sodium thiosulphate solution, wash with 100 ml. of cold, saturated sodium chloride solution, and dry with anhydrous magnesium sulphate. Remove the ether by flash distillation (Section 11,13 compare Fig. II, 13, 4) on a steam bath and distil the residue from a Claisen flask with fractionating side arm under diminished pressure. Collect the 1 4-diiodobutane at 110°/6 mm. the yield is 65 g. 

B. Conversion of maleic acid into fumaric acid. Dissolve 10 g. of maleic acid in 10 ml. of warm water, add 20 ml. of concentrated hydrochloric acid and reflux gently (provide the flask with a reflux condenser) for 30 minutes. Crystals of fumaric acid soon crystaUise out from the hot solution. Allow to cool, filter oflF the fumaric acid, and recrystallise it from hot. A -hydrochloric acid. The m.p. in a sealed capillary tube is 286-287°. 

C. Fumaric acid from furfural. Place in a 1-litre three-necked flask, fitted with a reflux condenser, a mechanical stirrer and a thermometer, 112 5 g. of sodium chlorate, 250 ml. of water and 0 -5 g. of vanadium pentoxide catalyst (1), Set the stirrer in motion, heat the flask on an asbestos-centred wire gauze to 70-75°, and add 4 ml. of 50 g. (43 ml.) of technical furfural. As soon as the vigorous reaction commences (2) bvi not before, add the remainder of the furfural through a dropping funnel, inserted into the top of the condenser by means of a grooved cork, at such a rate that the vigorous reaction is maintained (25-30 minutes). Then heat the reaction mixture at 70-75° for 5-6 hours (3) and allow to stand overnight at the laboratory temperature. Filter the crystalline fumaric acid with suction, and wash it with a little cold water (4). Recrystallise the crude fumaric acid from about 300 ml. of iif-hydrochloric acid, and dry the crystals (26 g.) at 100°. The m.p. in a sealed capillary tube is 282-284°. A further recrystaUisation raises the m.p. to 286-287°. 

It is believed that the red phosphorus is the true reducing agent and the iodine (or iodide) functions as a hydrogen carrier. This proc ure replaces the obsolete method of heating with red phosphorus and concentrated hydriodic acid in a sealed tube. 

Aminopyridine. In a 1 litre three-neoked flask, equipped with a sealed mechanical stirrer, reflux condenser, thermometer and inlet tube for nitrogen, place 300 ml. of dry toluene (1) aud 75 g. of fine granular sodamide (2) bubble a steady stream of nitrogen thi ough the toluene. Stir the mixtiue vigorously and heat the flask in an oil bath until the internal temperatime is 110° (the bath temperatime required is approximately 130°). Add 100 g. of pure dry pyridine (compare Section 11,47,22)... 

In figure 4 is shown how a separatory funnel and a pressure equalized addition funnel are made. The funnel part is just a PP funnel from the grocery store and what it is attached to is a stainless steel ball valve. See how the addition funnel is made by using a rubber stopper and an extra extension of tubing to the top of the funnel Well, that s how one can make a sealed addition funnel out of the ordinary glass separatory funnel that one gets with a distillation kit or from wherever. 

Now, contrary to popular opinions, this method need not be conducted in a sealed pipe bomb. Secondary amination by substitution is as much a reaction of opportunity as it is of brute force and heat. In fact, heating can tend to cause the reformation of safrole and isosafrole. So the simplest way to do this would be to use 500mL of ammonium hydroxide or alcoholic ammonia or, for those wishing to make MDMA or meth, 40% aqueous methylamine or alcoholic methylamine (to tell you the truth, methylamine is preferable in this method because it is more reactive that ammonia so yield will increase). This 500mL is placed in a flask and into it is poured a solution of 35g bromosafrole (30g phenylisopropyl-bromide) mixed with 50mL methanol. The flask is stoppered and stirred at room temperature for anywhere from 3 to 7 days. The chemist could also reflux the same mixture for 6-12 hours or she could throw the whole mix into a sealed pipe bomb (see How to Make section) and cook it for 5 hours in a 120-130°C oil bath. 

METHOD 3 [109]—1 part guaiacol and 2.5 parts MesSiSNa in 1,3-dimethyl-2-imidazoline heated at 185°C in a sealed pipe bomb gives 80-96% catechol. 

A mixture of 4-bromo-l-(4-methylphenylsulfonyl)indole (88 mg, 0.25 mmol), methyl a-acetamidoacrylate (91 mg, 0.64 mmol), PdCl2(PPh3)2 (16 mg, 0.023 mmol) and NaOAc (82 mg, 0.98 mmol) in EtjN (0.8 ml) and DMF (0.4 ml) was heated to 120°C in a sealed tube for 2 h. The tube was opened and the contents diluted with EtOAc and filtered through Celite. The EtOAc was washed successively with 10% HCl, sat. NaHC03 and brine and then dried (MgS04). The residue was purified by elution through silica gel with 10 1 benzene-EtOAc to give the product as a yellow solid (93 mg, 90%). 

A solution of l-methylpyrano[4,3-b]indol-3-one (1 mmol) and methyl vinyl ketone (5 ml) in toluene (5 ml) containing 5% Pd/C (40 mg) was heated for 48 h in a sealed tube at 110°C. The reaction mixture was evaporated in vacuo and the residue purified by silica gel chromatography to give the product in 80% yield. 

Hydroxy-4-methylthiazole failed to react when submitted to Friedel-Crafts benzoylation conditions (349) on the other hand, it reacted normally in Gattermann and in Reimer-Tiemann formylation reactions, affording the 5-formyl derivative (348). 4-Methylthiazole is insufficiently activated and fails to react under the same conditions. 2,4-Dimethylthiazole undergoes perfluoroalkylation when heated at 200° for 8 hr in a sealed tube with perfluoropropyl iodide and sodium acetate (116) (358). 

Butane lighters contain about 5% n butane and 95% isobutane in a sealed con tamer The pressure pro duced by the two com pounds (about 3 atm) is enough to keep them in the liquid state until opening a small valve emits a fine stream of the vaporized mixture across a spark which ignites it... 

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