Acids, organic ambient concentrations

Anhydrous aluminum triduotide, A1F., is a white crystalline soHd. Physical properties are Hsted ia Table 2. Aluminum duotide is spatingly soluble ia water (0.4%) and iasoluble ia dilute mineral acids as well as organic acids at ambient temperatures, but when heated with concentrated sulfuric acid, HF is hberated, and with strong alkah solutions, aluminates are formed. A1F. is slowly attacked by fused alkahes with the formation of soluble metal duotides and aluminate. A series of double salts with the duotides of many metals and with ammonium ion can be made by precipitation or by soHd-state reactions. 

Fig. 2-13. The effect of acid and base concentration on the resolution of propranolol on teicoplanin CSP (250 x 4.6 mm) in the new polar organic mode. The flow rate was 2.0 mL min at ambient temperature (23 °C).

Grosjean, D., Organic Acids in Southern California Air Ambient Concentrations, Mobile Source Emissions, in Situ Formation, and Removal Processes, Environ. ScL Technol., 23, 1506-1514(1989). 

Potassium permanganate (4.59 g) was then slowly added and the mixture stirred for 2 hours on an iced bath for 18 hours at ambient temperature. The solution was then treated with 720 ml of ethyl acetate, 540 ml of water, and sodium hydrogensulfite and the pH raised to 1 using 1.0 M hydrochloric acid. The organic layer was separated and washed three times with 1.0 M hydrochloric acid and then concentrated and the residue washed successively with 600 ml of water, 600 ml of methanol, and three times with 600 ml of water. The residue was then dissolved in THF and reprecipitated in excess methanol, dried, and 5.30 g of product isolated having an Mn of 13,200 Da with an Mw of 18,300 Da and containing 8 mol% carboxylic acid. 

Proper selection of the material of construction can avoid many catastrophic corrosion problems. Stainless steel is an excellent choice for many organic acids, but is rapidly attacked by halogen acids. Although readily attacked at elevated temperature, pressure, and concentration, stainless steel offers some protection against sulfuric, nitric, and phosphoric acid at low concentration and ambient temperature. 

Grosjean, D., Organic acids in southern California air ambient concentrations, mobile source emissions, in situ formation and removal processes. Environ. Sci. TechnoL, 23, 1506-1514, 1989. 

Table 13.8 presents chemical compounds that have been identified as primary organic aerosol components (Rogge et al., 1991, 1993a-e) together with their annual average ambient mass concentrations in the Los Angeles air basin. These ambient concentrations are the cumulative results of a variety of primary sources and secondary aerosol production. Normal alkanoic acids, aliphatic dicarboxylic acids, and aromatic polycarboxylic acids are... 

CITRIC ACID. (HOOC)CH.C (OH)(COOH) CH2COOH. In laboratory tests. 1100 alloy was resistant to aqueous solutions of citric acid at ambient temperature. While increased concentration had little effect, increasing temperature caused the corrosivity of the solutions to increase substantially. The presence of chlorides or heavy metals increases the corrosivity of these solutions. Aluminum has no harmful action on the organisms used in the manufacture of citric acid and is suitable for equipment such as fermenting vats, crystallizers, solution storage vats, and piping. Alloy 356.0 valves have been used for handling citric acid solutimis. See also Ref U) p. 130, (2) p. 199. (3) pp, 131, 209, (4)pp. 22. 25. 26. 27, 28, 29. 30. 31, 109, 110, 113. (7) p. 65. 

Equipment from mild steel usually is suitable for handling organic solvents, with the exception of those that are chlorinated, cold alkaline solutions (even when concentrated), sulfuric acid at concentrations greater than 88%, and nitric acid at concentrations greater than 65% at ambient temperatures [7]. 

M. Watt and J. Evans, Linking development and determinacy with organic acid efflux from proteoid roots of white lupin grown with low phosphorus and ambient or elevated atmospheric COi concentration. Plant Pltywlol. 120 705 (1999). 

B. 1-(Hydroxymethyl)cycloheptanol. To a 100-mL round-bottomed flask equipped with a stirring bar and a reflux condenser are added 1-[(methoxymethoxy)methyl]cycloheptanol (3.90 g, 20.7 mmol), methanol (50 mL), and hydrochloric acid (12.1 N, 0.75 mL). The reaction mixture is heated to 55°C for 1.5-2 hr (Note 8). After completion of the reaction, as indicated by TLC (Note 8), the reaction mixture is cooled to ambient temperature and carefully diluted with 35 mL of saturated aqueous sodium bicarbonate and stirred for 30 min. The methanol is removed under reduced pressure using a rotary evaporator and the remaining aqueous mixture is extracted with three 40-mL portions of ethyl acetate. The combined organic layers are washed once with 15 mL of saturated aqueous sodium chloride, dried over anhydrous sodium sulfate, filtered, and concentrated at reduced pressure using a rotary evaporator to afford 2.9 g of crude product as a pale yellow oil. The crude product is... 

The Swiss law for water protection does not indicate a concentration hmit for aluminium in surface waters. Therefore, in order to better assess the measured aluminium concentrations, we compared them with the concentration limits existing in the US. The chronic US National Ambient Water Quality Criteria [19] for total aluminium at a pH of 6.5-9 is 87 pg 1, indicating that the average value over 4 days should not exceed this value more than once every 3 years. However, since aluminium seems to be more toxic at low pH s the result is that in acidic waters the acceptable chronic value of total aluminium may be even lower. We conclude that aluminium concentrations in our three most acid lakes are probably high enough to cause toxic effects on organisms. 

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