Dean-Stark analysis

To effectively monitor the separation efficiency of the particular treatment equipment, two specific methods are employed centrifugation (discussed briefly under Testing Procedures ) and the Dean-Stark analysis. The Dean-Stark analysis determines the fractional composition of oil-hydrocarbon, water, and solids of an emulsion stream by using a distillation process. Its results for heavy-oil emulsions are generally more reliable than those obtained by centrifugation however, the results of centrifugation are... 

Table B.4 represents a composite mass balance for the entire pilot-plant operation. Any differences in the totals are directly attributable to sampling error, experimental error in conducting the Dean-Stark analysis, and the flow measurement error.

Table B.2. Dean-Stark Analysis vs. Centrifuge Comparative Results of Bitumen Cut...

Microscopic wettability tests performed at CAN MET have demonstrated that solids from oil sands plants (froth, middlings, and tailings) prepared by solvent extraction to remove bitumen and water (Dean Stark) analysis were all oil wetted. It is known, however, that the bulk of the oil sands solids are in fact water wet. Since solvent extraction is the common method for preparation of oil field solids, it raises some questions about the utility of wettability tests on extracted solids using the conventional methods mentioned earlier. 

Assemble a flask (30 mL or 123 mL, see below), a Dean Stark trap, and a condenser, and preextract with toluene for three hours. Preextraction will ensure that the glassware is as clean as possible and minimize crosscontamination problems. Discard the used toluene, or pool it for later analysis to verify the cleanliness of the glassware. 

Synthesis of Siloxane-Polyimide Elastoplastics. In a typical polymerization, a 5-L, three-neck, round-bottom flask equipped with an overhead mechanical stirrer, a Dean-Stark trap with condenser and a nitrogen inlet, and a thermometer was charged with 484.00 g (0.2406 mol) of D2o-DiSiAn, 41.61 g (0.431 mol) of mPD, 19.52 g (3 wt %) of 2-hydroxypyridine, and 2 L of o-dichlorobenzene. The mixture was warmed to 100 °C for 1 h to dissolve the monomers and the catalyst. The polyamic acids precipitated and then redissolved when the mixture was warmed to 150 °C for 2 h. To the oligomer solution was added 99.13 g of BPADA dissolved in 200 mL of o-dichlorobenzene. The mixture was maintained at 150 °C for an additional 2-h period to ensure incorporation of the dianhydride and then warmed to reflux. After approximately 100 mL of a solvent-water mixture had been removed, the solution was maintained at 180 °C for 40 h. The mixture was cooled to room temperature and diluted with 1 L of methylene chloride. Polymer was isolated from the solution by a slow addition of the polymer solution to 4 L of methanol. The resulting slurry was filtered, and the polymer was redissolved in 4 L of methylene chloride, extracted three times with 2 N aqueous HCl to remove catalyst, washed with water, dried with magnesium sulfate, reprecipitated into methanol as before, filtered, and dried in vacuo at 100 °C to obtain 522 g (85%) of a rubbery material with an IV of 0.50 dL/g. IR, NMR, and Si NMR spectroscopic analysis indicated the absence of amic acid functionalities that could be present if imidization is incomplete. 

B. (5S)-(d-Menthyloxy)-2(5H)-furanone. A 500-mL, round-bottomed flask equipped with a magnetic stirring bar, 10-mL Dean-Stark trap, and reflux condenser is charged with d-menthol (51.9 g, 0.330 mol), 5-hydroxy-2(5H)-furanone (37.3 g, 0.370 mol), D-(-i-)-camphorsulfonic acid (3.96 g, 0.170 mol), and 190 mL of dry benzene (Note 8). The stirred suspension is heated to reflux under argon with an oil bath preheated to 100°C (Note 9). After 1-2 hr, a total of 5.1 mL of water is collected and no residual menthol is apparent by TLC analysis (Note 10). The reaction mixture is cooled in an ice bath and treated carefully with 100 mL of saturated sodium bicarbonate solution. After completion of the addition, stirring is maintained for 90 min as the mixture is allowed to warm to room temperature. The... 

Sample Number Dean-Stark Centrifugation Analysis Method % Difference ... 

Triethylenetetramine was purchased from Aldrich Chemical Company, Inc., as a hydrate. Anhydrous triethylenetetramine must be used in this procedure. The anhydrous tetraamine was obtained by azeotropic distillation of water (Dean-Stark trap, 3 days) from a solution of 125 g of the commercial hydrate in 150 mL of toluene. Analysis by 1H NMR verified the removal of water, and no further purification was necessary. 

In a three-necked flask equipped with reflux-condenser and magnetic stirrer, 2,3-dimethyl-2,3-epoxybutane 2 (5 mmol), solvent (50 mL), demi-water (10 mmol) and an exact amount of internal standard 1,3,5-tri-terf-butylbenzene were mixed and, under stirring, the solution was warmed to 45 °C. The catalyst was added at once (t = 0). The reaction was followed in time by taking samples during the reaction and the products were analyzed by GC and GC-MS. After complete conversion of the starting substrate to pinacol 3, the reflux-condenser was replaced by a Dean-Stark apparatus and the reaction temperature raised to 80 °C. The formation of 4 was followed by taking samples of the reaction mixture followed by GC analysis. 

A mixture of 356 mg ClC4F8S02CH2C0Ph (0.84 mmol), 43 mg benzaldehyde (0.4 mmol), and 78 /xL piperidine in 16 mL toluene was refluxed for 1 h with azeotropic removal of water using a Dean-Stark trap. TLC analysis indicated the reaction was completed. The mixture was cooled to room temperature, the solvent was removed under reduced pres sure, and the residue was column chromatographed (hexane/ethyl ether, 10 1) to give 213 mg (2/ ,35 )-2-benzoyl-3-phenyl-4-(4 -chloro-perfluorobutylsulfonyl)-4-phenyl-2,3-dihydrofuran, in a yield of 84%. 

The final example by Severin et al. indicates as to where the dynamic covalent synthesis of superstructures may lead to." Driven by a previous observation that boronic ester-based macrocycles with pendent aldehyde groups could be functionalized with amines, they investigated the possibility of performing boronic ester and imine condensation reactions simultaneously. In the first attempt, a mixture of 3-formylphenylboronic acid 14, pentaerythritol 15, and 1,4-diaminobenzene 16 in tetrahydrofuran/toluene was heated in a flask equipped with a Dean-Stark trap (Figure 8a). Analysis of the formed products revealed the formation of macrocycle 17 as a result of a [4-F2-F2] condensation with a yield of 44%. Prompted by this success, they performed the polycondensation reaction on a mixture of 4-formylphenylboronic acid 18, pentaerythritol 15, and tris(2-aminoethyl)amine 19, rather than the linear 1,4-diaminobenzene (Figure 8b). With a remarkable yield of 82%, the macrobicyclic cage 20 was spontaneously formed as a result of the condensation of six boronic acid molecules, three pentaerythritol molecules, and two triamine molecules. A total of 18 covalent bonds were... 

This result was unprecedented, because normal dehydration between the components in toluene/10% methanol under reflux in a Dean-Stark apparatus provided no nueleation. The average diameter of the submicrospheres was estimated to be 870 100 nm, based on field-emission scanning electron microscopy (FE-SEM) images of 1000 particles. Spectroscopic analysis using... 

High Temperature. A mixture of 31.79 g of 50% aqueous sodium hydroxide, 45.35 g of BPA, 180.2 ml of DMSO and 180.2 ml of toluene was heated at reflux under nitrogen until all visible traces of water had been removed (Dean Stark Trap). The condensed distillate was then passed through a recirculating trap filled with molecular sieves to complete the drying. The toluene was then distilled from the system. The temperature of the mixture was maintained at 110 C while 25.26 g of methylene chloride was added dropwise over a period of 20 minutes. A slight precipitate formed almost as soon as the first drops of methylene chloride were added. The mixture was stirred for an additional 15 minutes and it was then added to methanol. The resulting solid ( was collected by filtration and dried. [n] = 0.88 dl/g, 7.1% cyclics by L.C. analysis. 

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