Carbon dioxide collection

Process Put three or four lumps of charcoal in the combus ion tube and connect the different parts of the apparatus. Regulate the flow of carbon dioxide so that the rate is (approximately) a bubble a second. Stop the leaks, if any are detected. Heat the whole combustion tube at first, and finally concentrate the heat where the charcoal is located. Collect all the gas evolved, but reject the first two bottles, as they contain air (and possibly carbon dioxide). Collect two or three more bottles, cover with glass plates, and set them aside temporarily. Stop the generator, remove the delivery tube from the trough, and gradually cool the combustion tube. Test the gas thus —... 

Dumas method. Condensation of nitrogenous organic compounds with copper oxide in a stream of carbon dioxide, collection of the elementary nitrogen over aqueous potassium hydroxide, and volumetric estimation in an azotometer. Any nitrogen oxides formed are reduced by passage over a red-hot copper spiral. 

Figure 4.14 A background spectrum of air, showing the absorption bands due to water vapor and carbon dioxide. Collected on a Paragon 1000 FTIR spectrometer, PerkinElmer Instruments, Shelton, CT (www.perkinelmer.com).

Carbon dioxide collected from the fractions for isotope measurements was substantially higher than minimum requirements and ranged from 40 to 500 /rmol (480-6000 /rg C) from the SM Basin and from 20 to 290 /rmol (240-3480 /rg C) from the Antarctic sediment. Protokerogen from the Antarctic sediment was the smallest sample size used in this study yielding 20 /rmol of carbon dioxide. However, nitrogen values were uniformly low ranging from 2 to 4 /rmol from the SM Basin and from 2 to 10 /rmol in the Antarctic sediment. 

SCE-based processes such as GAS process, SAS process, aerosol solvent extraction system (ASES), SEDS address low solubility of the compounds in SCCO2. In these processes, the drug, polymer, or both are dissolved in an organic solvent to form a solution. Solvents used may include dimethyl sulfoxide, N-methyl pyrrolidone, methanol, ethanol, acetone, chloroform, or isopropanol. To successfully produce ASD, the drug and polymer should exhibit limited solubility in SCF and the organic solvent should be miscible with carbon dioxide. Collection of the precipitated particles in the antisolvent is carried out in the same vessel where solvent extraction takes place. The particles are collected on a filter unit located at the bottom of the vessel. 

A graph of total volume of carbon dioxide collected against time... 

Figure 11.23 A graph showing the volume of carbon dioxide collected against time for the reaction between excess powdered calcium carbonate and hydrochloric acid... 

A construction worker was killed in a trench near Barnsley, South Yorkshire, UK, when carbon dioxide collected in tiie base of the trench. The trench had been constructed through colliery spoil in an area of historic mining (New Civil Engineer, 1999)... 

Ethyl bromide soon distils over, and collects as heavy oily drops under the water in the receiving flask, evaporation of the very volatile distillate being thus prevented. If the mixture in the flask A froths badly, moderate the heating of the sand-bath. When no more oily drops of ethyl bromide come over, pour the contents of the receiving flask into a separating-funnel, and carefully run oflF the heavy lower layer of ethyl bromide. Discard the upper aqueous layer, and return the ethyl bromide to the funnel. Add an equal volume of 10% sodium carbonate solution, cork the funnel securely and shake cautiously. Owing to the presence of hydrobromic and sulphurous acids in the crude ethyl bromide, a brisk evolution of carbon dioxide occurs therefore release the... 

Chill the concentrated solution of the amine hydrochloride in ice-water, and then cautiously with stirring add an excess of 20% aqueous sodium hydroxide solution to liberate the amine. Pour the mixture into a separating-funnel, and rinse out the flask or basin with ether into the funnel. Extract the mixture twice with ether (2 X25 ml.). Dry the united ether extracts over flake or powdered sodium hydroxide, preferably overnight. Distil the dry filtered extract from an apparatus similar to that used for the oxime when the ether has been removed, distil the amine slowly under water-pump pressure, using a capillary tube having a soda-lime guard - tube to ensure that only dry air free from carbon dioxide passes through the liquid. Collect the amine, b.p. 59-61°/12 mm. at atmospheric pressure it has b.p. 163-164°. Yield, 18 g. 

Its purpose is twofold first of all to prevent any particles of the analysis sample, which is to be added next, from percolating through the coarse porous w ire-form " copper oxide and so into that portion of the tube heated by the furnace and secondly as a heat insulator, to present the sample being heated too rapidly by the nearby furnace. Both these safeguards are required, as otherwise some portion of the sample would be decomposed as soon as the furnace was sw-itched on the nitrogen so produced would be carried away during the initial sweeping of the air out of the tube with the carbon dioxide stream, and would not be collected. Low results w ould thus be obtained. 

The combustion. The tap T2 is closed, T3 opened and the reservoir J raised (Fig. 87), to make sure that no air has been collected at the top of the nitrometer tube a small quantity of potash is left in H when tap T3 is closed and the reservoir J then lowered again. The carbon dioxide generator is switched off and tap T2 slowly turned on until it is fully opened. 

Mix together in a 250 ml. flask carrying a reflux condenser and a calcium chloride drying tube 25 g. (32 ml.) of freshly-distilled acetaldehyde with a solution of 59-5 g. of dry, powdered malonic acid (Section 111,157) in 67 g. (68-5 ml.) of dry pyridine to which 0-5 ml. of piperidine has been added. Leave in an ice chest or refrigerator for 24 hours. Warm the mixture on a steam bath until the evolution of carbon dioxide ceases. Cool in ice, add 60 ml. of 1 1 sulphuric acid (by volume) and leave in the ice bath for 3-4 hours. Collect the crude crotonic acid (ca. 27 g.) which has separated by suction filtration. Extract the mother liquor with three 25 ml. portions of ether, dry the ethereal extract, and evaporate the ether the residual crude acid weighs 6 g. Recrystallise from light petroleum, b.p. 60-80° the yield of erude crotonic acid, m.p. 72°, is 20 g. 

Dissolve 57 g. of dry malonic acid in 92 5 ml. of dry P3rridine contained in a 500 ml. round-bottomed flask, cool the solution in ice, and add 57 g. (70 ml.) of freshly distilled n-heptaldehyde (oenanthol) with stirring or vigorous shaking. After a part of the aldehyde has been added, the mixture rapidly seta to a mass of crystals. Insert a cotton wool (or calcium chloride) tube into the mouth of the flask and allow the mixture to stand at room temperature for 60 hours with frequent shaking. Finally, warm the mixture on a water bath until the evolution of carbon dioxide ceases (about 8 hours) and then pour into an equal volume of water. Separate the oily layer and shake it with 150 ml. of 25 per cent hydrochloric acid to remove pyridine. Dissolve the product in benzene, wash with water, dry with anhydrous magnesium sulphate, and distil under reduced pressure. Collect the ap-nonenoic acid at 130-13272 mm. The yield is 62 g. 

In a 250 ml. conical flask mix a solution of 14 g. of sodium hydroxide in 40 ml. of water and 21 g. (20 ml.) of pure benzaldehyde (Section IV,115). Add 15 g. of hydroxylamine hydrochloride in small portions, and shake the mixture continually (mechanical stirring may be employed with advantage). Some heat is developed and the benzaldehyde eventually disappears. Upon coohiig, a crystalline mass of the sodium derivative separates out. Add sufficient water to form a clear solution, and pass carbon dioxide into the solution until saturated. A colourless emulsion of the a or syn-aldoxime separates. Extract the oxime with ether, dry the extract over anhydrous magnesium or sodium sulphate, and remove the ether on a water bath. Distil the residue under diminished pressure (Fig. 11,20, 1). Collect the pure syn-benzaldoxime (a-benzald-oxime) at 122-124°/12 mm. this gradually solidifies on cooling in ice and melts at 35°. The yield is 12 g. 

Add the salt to dilute hydrochloric acid (prepared from 28 ml. of the concentrated acid and 150 ml. of water) contained in a 500 ml. flask fitted with a reflux condenser. Warm the mixture gently carbon dioxide is evolved and an oil separates. Heat on a steam bath for 90 minutes, cool, and extract the oil with 75 ml. of benzene. Wash the extract with 100 ml. of water, and distil the benzene solution under reduced pressure from a Claisen flask. Collect the a-phenylpropionaldehyde at 90-93°/10 mm. the yield is 30 g. 

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