Reagent Grade Water

Methanol, ethanol, acetonitrile, benzene, trifluoroacetic anhydride, triethylamine, distilled water reagent grade (Wako Pure Chemical Industries, Ltd, Japan) Methanol, distilled water specially prepared reagent for HPLC (Wako Pure Chemical Industries, Ltd, Japan)... 

Methanol, n-hexane, ethyl acetate, distilled water, sodium chloride, sodium sulfate, reagent grade for residue analysis (Wako Pure Chemical Industries, Ltd, Japan) Acetonitrile, methanol, distilled water, reagent grade for high-performance liquid chromatography... 

Sulfurous acid (H2S03) is a colorless liquid, prepared by dissolving sulfur dioxide (S02) in water. Reagent grade sulfurous acid contains approximately 6% sulfur dioxide in solution. 

These points were investigated by a series of experiments involving the water washing of a Peruvian cotton textile that was approximately 800 years old. Various treatments were tested by subjecting suitable size samples to washing with tap water, reagent grade distilled-deionized... 

A pyrochlore of the approximate composition Pb2 [Ru 133Pbo 67] 06 S may be synthesized by first preparing an aqueous solution source of lead and ruthenium cations in a 2 1 lead-to-ruthenium ratio as follows 5.0 g of commercially available Ru(N03)3 solution, 10% (wt.) ruthenium metal (0.005 mole ruthenium metal) is diluted with 25 mL of distilled water. Reagent grade Pb(N03)2 (3.277 g, 0.010 mole) is dissolved in 100 mL of distilled water and added to the ruthenium aqueous solution. This aqueous solution of lead and ruthenium is then stirred for approximately 10 min. 

Amino acids are distributed ubiquitously throughout much of the earth s crust, including the atmosphere (IJ. Their occurrence and important role in living organisms are well known, but amino acids have also been found in fossils and rocks hundreds of millions of years and even billions of years old (2. Amino acids have been reported at parts-per-billion levels in extra-terrestrial samples such as the Apollo moon rocks as well as in several meteorites (3,4). Even distilled water, reagent-grade HCl and other chemicals frequently contain trace amounts of amino acids. Figure 1 summarizes the levels of amino acids found in several samples of environmental Interest. 

Coumarin, potassium bromide, and potassium ferrioxalate were reagent grade and used without further purification. 3-Cyclodextrin was purchased from Nichiden Chemical Co. Ltd. and purified by recrystallization once from 1-propanol and twice from water. Reagent grade organic solvents were purified and dried by standard methods [19]. Cis- and trans-head-to-head dimers of coumarin were obtained from the irradiation of coumarin in formic acid and in benzene without or with a small amount of benzophenone, respectively, by the similar method of Schenck and Krauch [12,14], An inclusion complex of coumarin with 3-cyclodextrin was obtained as follows equimolar aounts of coumarin and the cyclodext-... 

A 1.6.1 Distilled Water—Reagent grade as defined by Type III of Specification D 1193, freezing point 0.0°C. 

Acetone. The analytical reagent grade contains about 1 per cent, of water and meets most requirements. Synthetic acetone of a high degree of purity (water content about 1 per cent.) is also available as a technical product. 

The analytical reagent grade is suitable for most purposes. The commercial substance may be purifled by shaking for 3 hours with three portions of potassium permanganate solution (5 g. per litre), twice for 6 hours with mercury, and Anally with a solution of mercuric sulphate (2-5 g. per litre). It is then dried over anhydrous calcium chloride, and fractionated from a water bath at 55-65°. The pure compound boils at 46-5°/760 mm. 

Standard Manganese(ll) Solution. Dissolve exactly 16.901 g ACS reagent grade manganese(II) sulfate hydrate in water and dilute to 1 E. 

AgN03 (P) 169.89 Weigh the desired amount of ACS reagent grade AgNOg, dried at 105°C for 2 hr, and dissolve in double distilled water. Store in amber container and away from light. Check against NaCl. 

Hg(N03)2 H3O 342.62 Dissolve the reagent grade salt in distilled water and dilute to desired volume. Standardize against NaCl. 

Mercurous Nitrate. Mercurous nitrate [10415-75-5] Hg2N20 or Hg2(N02)2, is a white monoclinic crystalline compound that is not very soluble in water but hydrolyzes to form a basic, yellow hydrate. This material is, however, soluble in cold, dilute nitric acid, and a solution is used as starting material for other water-insoluble mercurous salts. Mercurous nitrate is difficult to obtain in the pure state directly because some mercuric nitrate formation is almost unavoidable. When mercury is dissolved in hot dilute nitric acid, technical mercurous nitrate crystallizes on cooling. The use of excess mercury is helpful in reducing mercuric content, but an additional separation step is necessary. More concentrated nitric acid solutions should be avoided because these oxidize the mercurous to mercuric salt. Reagent-grade material is obtained by recrystaUization from dilute nitric acid in the presence of excess mercury. 

Benzoic acid [65-85-0] M 122.1, m 122.6-123.1, pK 4.12. For use as a volumetric standard, analytical reagent grade benzoic acid should be carefully fused to ca 130 (to dry it) in a platinum crucible, and then powdered in an agate mortar. Benzoic acid has been crystd from boiling water (charcoal), aq acetic acid, glacial acetic acid, C6H6, aq EtOH, pet ether (b 60-80 ), and from EtOH soln by adding water. It is readily purified by fractional crystn from its melt and by sublimation in a vacuum at 80. ... 

Aluminium fluoride (anhydrous) [7784-18-4] M 84.0, m 250°. Technical material may contain up to 15% alumina, with minor impurities such as aluminium sulfate, cryolite, silica and iron oxide. Reagent grade AIF3 (hydrated) contains only traces of impurities but its water content is very variable (may be up to 40%). It can be dried by calcining at 600-800° in a stream of dry air (some hydrolysis occurs), followed by vacuum distn at low pressure in a graphite system, heated to approximately 925° (condenser at 900°) [Henry and Dreisbach J Am Chem Soc 81 5274 1959]. 

Potassium iodate [7758-05-6] M 214.0, pK 0.80 (for HIO3). Crystd twice from distilled water (3mL/g) between 100° and 0°, dried for 2h at 140° and cooled in a desiccator. Analytical reagent grade material dried in this way is suitable for use as an analytical standard. 

Vanadium (metal) [7440-62-2] M 50.9, m 1910°, d 6.0. Cleaned by rapid exposure consecutively to HNO3, HCl, HF, de-ionised water and reagent grade acetone, then dried in a vacuum desiccator. 

The ether should be reagent grade but not sodium-dried. The traces of water present destroy excess reagent, leading to a cleaner product. 

B. 3-Hydroxycinchoninic acid. A 3-1., four-necked flask (Note 1) is equipped with a sealed mechanical stirrer, gas inlet tube, gas outlet consisting of a 1-mm. capillary (Note 7), and thermometer. The flask is charged with a freshly prepared solution containing 448 g. (8 moles) of reagent grade (85% minimum assay) potassium hydroxide and 900 ml. of water. The solution (hot from dissolution of potassium hydroxide) is stirred and 147 g. (1 mole) of isatin (Note 8) is introduced. The solid quickly dissolves to give an orange-yellow solution. 

After the product has been collected as before, the filter cake is pressed well, sus[)cnded in 800 ml. of water, and dissolved by stirring and adding the miniimim (luaniily of reagent grade concentrated a( ueoiis ammonia (approximalely 60 ml.). A small... 

The product of a second step is the methyl aceloacelic ester enamine of N-2-amino-2-(1,4-cyclohexadienyl)acelic acid sodium salt. 306 mg D-2-amino-2-(1,4-cyclohexadienyl)-acelic acid (2.00 mmol) are dissolved by warming in a solution of 108 mg of NaOCHj (2.00 mmol) in 4.3 ml reagent grade MeOH. 255 mg (0.24 ml, 2.20 mmol) methyl ace-loacelale are added and the mixture refluxed for 45 minutes. The MeOH Is almost totally stripped off in vacuo. Five milliliters benzene are added and distilled off to a small residual volume. The addition and distillation of benzene is repealed to insure complete removal of the MeOH and water. The product crystallizes out overnight from a small residual volume of benzene. It is filtered off, washed with benzene, and dried in vacuo. 

In a 1-1. three-nccked, round-bottomed flask equipped with a mechanical stirrer, reflux condenser, and powder funnel are placed 180 ml. of reagent grade chloroform, 16.0 g. (0.16 mole) of cyclobutanecarboxylic acid (Note 1), and 48 ml. of concentrated sulfuric acid. The flask is heated in an oil bath to 45-50°, and 20.0 g. (0.31 mole) of sodium azide (Note 2) is added over a period of 1.5 hours (Note 3). After the addition of sodium azide is complete, the reaction mixture is heated at 50° for 1.5 hours. The flask is cooled in an ice bath, and approximately 200 g. of crushed ice is added slowly. A solution of 100 g. of sodium hydroxide in 200 ml. of water is prepared, cooled to room temperature, and then added slowly to the reaction mixture until the pH of the mixture is approximately 12—13. The mixture is poured into a 2-1. three-necked, round-bottomed flask, the... 

Chloroaeetophenone oxime was prepared by a modification of the method described by Shriner, Fuson, and Curtin.5 A mixture of 100 g. (0.65 mole) of reagent-grade 4-chloroacetophenone, 300 ml. of water, 200 ml. of aqueous 10% sodium hydroxide, 50g. (0.72 mole) of hydroxyl-amine hydrochloride, and 500 ml. of ethanol is heated at reflux in a 2-1. round-bottomed flask for 2 hours. The crystals that separate on cooling in an ice bath are recovered by filtration and air dried. The product is added to approximately 1 1. of hexane, and the mixture is... 

N)-Ethy 1 lactate (98%) and imidazole (99+%) were purchased from Aldrich Chemical Co. TBDMSC1 was purchased from FMC Corporation (submitters) or Aldrich (checkers). A newly opened bottle of dimethylformamide (ACS Reagent grade, 0.02% water) was used as received. 

The checkers purchased [(COD)RuCl2]n from Fluka (purum quality), BINAP from Aldrich (97 %), and toluene (HPLC grade) and triethylamine (reagent grade) from Fisher Scientific the latter was distilled from CaH2 under Ar prior to use. The submitters dried toluene and triethylamine over 4 A molecular sieves. Karl-Fischer titration indicated <200 pg/mL water. 

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