Carbon dioxide, free

This carbon dioxide-free solution is usually treated in an external, weU-agitated liming tank called a "prelimer." Then the ammonium chloride reacts with milk of lime and the resultant ammonia gas is vented back to the distiller. Hot calcium chloride solution, containing residual ammonia in the form of ammonium hydroxide, flows back to a lower section of the distiller. Low pressure steam sweeps practically all of the ammonia out of the limed solution. The final solution, known as "distiller waste," contains calcium chloride, unreacted sodium chloride, and excess lime. It is diluted by the condensed steam and the water in which the lime was conveyed to the reaction. Distiller waste also contains inert soHds brought in with the lime. In some plants, calcium chloride [10045-52-4], CaCl, is recovered from part of this solution. Close control of the distillation process is requited in order to thoroughly strip carbon dioxide, avoid waste of lime, and achieve nearly complete ammonia recovery. The hot (56°C) mixture of wet ammonia and carbon dioxide leaving the top of the distiller is cooled to remove water vapor before being sent back to the ammonia absorber. 

To the residue is added 10 c.c. of dilute phosphoric acid, prepared by mixing about 3 5 c.c. of 88 per cent, acid with 100 c.c. of carbon dioxide-free distilled water. 

Some environmentalists have also touted natural gas as a way station on the road to a hydrogen fuel (carbon dioxide-free) economy. As seen in Table 1, per unit of energy released, natural gas generates about 23 percent less carbon dioxide than gasoline and about 30 percent less than heavy fuel oil. This is helpful in reducing greenhouse emissions, but the other excellent properties of natural gas are even... 

Notes. (1) In order to obtain sharp end points all de-ionised water used should be carbon-dioxide-free, as far as is possible. 

P2. 0.025m Phosphate buffer. Dissolve 3.40g of KH2P04 and 3.55 g of Na2HP04 (dried for 2 hours at 110-113 °C) in carbon-dioxide-free water and dilute to 1 kg. The solution is stable when protected from undue exposure to the atmosphere. 

Dissolve 2.5 g in carbon dioxide-free water R, and dilute to 25 mL with the same solvent. The solution is clear, and not more intensely colored than intensity 6 of the range of reference solutions of the most appropriate color. 

Various workers have discussed the determination of total alkalinity and carbonate [ 10-12], and the carbonate bicarbonate ratio [ 12] in seawater. A typical method utilises an autoanalyser. Total alkalinity (T milliequivelents per litre) is found by adding a known (excess) amount of hydrochloric acid and back titrating with sodium hydroxide solution a pH meter records directly and after differentiation is used to indicate the end-point. Total carbon dioxide (C milliequivelents per litre of HCO3 per litre) is determined by mixing the sample with dilute sulfuric acid and segmenting it with carbon dioxide-free air, so that the carbon dioxide in the sample is expelled into the air segments. The air... 

Experiments involving the release of radioactive carbon dioxide from MSMA-14C treated soils were conducted in a system consisting of two test tubes connected in series. One tube contained 5g of treated soil (at 10 and lOOppm of monosodium methane arsenic acid carbon dioxide while a second tube contained a trapping mixture, 2-methoxyethanol and monoethanolamine (7-10, v/v). Carbon dioxide-free air was passed over the soil and metabolic 14CO was collected in the trapping solution. The soils studied were Sharkey cldy, Hagerstown silty clay loam, Cecil sandy loam, and Dundee silty clay loam. All soils were initially adjusted to field capacity and maintained at 28-30°C the evolved 14CO was sampled periodically. Some properties of these soils are shown in Tabfe 13.1. 

Experiments were made in a nitrogen atmosphere using reagent grade chemicals and triply distilled carbon dioxide-free water. Standard solutions of... 

Procedure Weigh accurately about 1.5 g of sodium hydroxide and dissolve in about 40 ml of carbon-dioxide free distilled water (i.e., boiled and cooled DW). Cool and titrate with 1 N sulphuric acid using phenolphthalein solution as indicator. When the pink colour of the solution is discharged record the volume of acid solution required. 

Preparation of 0.1 M Tetrabutylammonium hydroxide (1 Litre) Dissolve 40 g of tetrabutylammonium iodide in 90 ml of anhydrous methanol, add 20 g of finely powdered silver oxide and shake vigorously for 1 hour. Centrifuge a few ml of the mixture and test the supernatant liquid for iodides. If a positive reaction is obtained add a further 2 g of silver oxide and shake for 30 minutes. Repeat this procedure until the mixture is free from iodides, filter through a fine sintered-glass filter and wash the reaction vessel and filter with three 50-ml quantities of toluene. Add the washings to the filtrate and add sufficient toluene to produce 1000 ml. Pass dry carbon-dioxide free N2 through the solution for 5 minutes. 

Soil Benzidine was added to different soils and incubated in the dark at 23 °C under a carbon dioxide-free atmosphere. After 1 yr, 8.3 to 11.6% of the added benzidine degraded to carbon dioxide primarily by microbial metabolism and partially by hydrolysis (Graveel et al, 1986). Tentatively identified biooxidation compounds using GC/MS include hydroxybenzidine, 3-hydroxybenzidine, 4-amino-4 -nitrobiphenyl, A(A -dihydroxybenzidine, 3,3 -dihydroxybenzidine and 4,4 -dinitrobiphenyl (Baird et al, 1977). Under aerobic conditions, the half-life was estimated to be 2 to 8 d (Lu et ah, 1977). 

Biological. 1-Naphthylamine added to three different soils was incubated in the dark at 23 °C under a carbon dioxide-free atmosphere. After 308 d, 16.6 to 30.7% of the 1-naphthylamine added to soil biodegraded to carbon dioxide (Graved et al., 1986). Li and Lee (1999) investigated the reaction of 10 mL of 7 mM 1-naphthylamine with 4 g of a Chalmers soil (pH 6.5, 11.1% sand, 72.8% silt, 16.0% clay). After 120 h, the soil was washed with acetonitrile and the extractant analyzed using GC/MS. The primary transformation product was a dimer tentatively identified as TV-(4-aminonaphthyl)-1-naphthylamine. The investigators hypothesized that the formation of this compound and two other unidentified dimers was catalyzed by minerals present in the soil. 

Four reagents are required for performance of this reaction. The first is a 0.1% ethanolic solution ofp-nitroso-A/iA -dimethylaniline. The second is pH 9.8 Clark and Lubs buffer, prepared by adding 40.8 mL of 0.2 M sodium hydroxide (carbon dioxide-free) to 50 mL of a 0.2M aqueous solution of both boric acid and potassium chloride. The third reagent is a 0.1% solution of phenol in ethanol, and the fourth reagent is a freshly prepared 1% aqueous solution of potassium ferricyanide. 

Fe(II)+KC103+6HCI = 6Fe(III)+KCl + 3H20 and Kao. +6HC1 = KC1 + 3HO + 3CL. Place about 2g NG in a tared beaker and retare. Dissolve in carbon dioxide-free HAc, and transfer... 

The difference in the conductivity of the calibration buffers and sample can cause a very large error on the sample measurement, due to junction potentials in different environments. Solid samples should be dissolved in purified water. It is necessary that the water be carbon dioxide-free. The presence of dissolved carbon dioxide will cause significant bias in the measurement of samples with low buffering capacity. For pH measurements with an accuracy of 0.01 to 0.1 pH unit, the limiting factor is often the electrochemical system (i.e., the characteristics of the electrodes and the solution in which they are immersed). 

Identification of Reaction Products. Carbon dioxide-free air was bubbled through the previously described reaction mixture. At the end of 6 hours, the carbon was removed by filtration, and the filtrate poured slowly into six times its volume of ethanol (95%). The precipitate which formed was recrystallized first from an ethanol-water solution and finally from a minimum amount of water. 

Experiment 1. Effect of Carbon Catalyst on Oxidation of Cobalt(ll) to Cobalt (III) and Formation of Ethylenediamine and Effect of Cobalt on Formation of Ethylenediamine. Carbon dioxide-free air was bubbled through the reaction mixture. Nine determinations each of the amounts of ammonia volatilized, the ethylenediamine concentration, and the cobalt (II) concentration were made over a period of 18 hours. The results are shown in Figure 1. 

Experiment 3. Rates of Formation of Ethylenediamine and Ammonia vs. Rate of Disappearance of Cobalt (II). Carbon dioxide-free air was bubbled through the solution. Ammonia, ethylenediamine, and cobalt (II) were determined periodically over a total reaction time of 5 hours. The results of this experiment are collected in Table I and plotted in Figure 3. The ammonia measured was actually the ammonia volatilized during the reaction, but it was calculated as moles per liter of solution in order to be consistent with the ethylenediamine and cobalt (II) results. 

White slicks used for making carbon dioxide free from air, according to Kreiisslcr. 

The scale formed under moderate temperatures is usually due to temporary (bicarbonate) hardness being converted into calcium carbonate, which occurs on heating or increase in alkalinity sufficient to result in calcium carbonate saturation. The solubility of calcium carbonate also affects corrosion since the alkalinity of dissolved carbon dioxide in the water is greatly reduced as the saturation equilibrium is approached. Ideally, at equilibrium the various forms of carbon dioxide (free C02, bicarbonate and carbonate) are so balanced that they cause neither scale nor corrosion. 

Catalysis and Chemical Synthesis in Carbon Dioxide Free-Radical Chain Reactions... 

G.L. Squadrito et al., Oxidative chemistry of nitric oxide The roles of superoxide, peroxynitrite, and carbon dioxide. Free Radic. Biol. Med. 25, 392-403 (1998)... 

Test for sensitivity A mixture of 0.1 mLof the methyl orange solution and 100 mL of carbon dioxide-free water K is yellow. Not mine than 0.1 mL of 0.1 N hydrochloric acid is required iti change tine Culii tu red. 

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