Chloroform, solution preparation, with phenol

Procedure Weigh accurately 0.5 g of phenol and dissolve in sufficient water to produce 500 ml in a volumetric flask. Mix 25.0 ml of this solution with 25.0 ml of 0.1 N potassium bromate in a 250 ml iodine flask and add to it 1 g of powdered KI and 10.0 ml of dilute hydrochloric acid. Moisten the glass stopper with a few drops of KI solution and place it in position. Set it aside in a dark place for 20 minutes while shaking the contents frequently in between. Add to it 10 ml of KI solution, shake the contents thoroughly and allow it to stand in the dark for a further duration of 5 minutes. Wash the stopper and neck of the flask carefully with DW, add 10 ml chloroform and titrate with the liberated iodine with 0.1 N sodium thiosulphate using freshly prepared starch as an indicator. Carry out a blank titration simultaneously and incorporate any necessary correction, if required. Each ml of 0.1 N potassium bromate is equivalent to 0.001569 g of C6H60. 

Procedure (Note Refer to Lead Limit Test, Appendix TTTR, for the solutions and the control.) Add 3 mL of Ammonium Citrate Solution and 0.5 mL of Hydroxylamine Hydrochloride Solution to the Sample Solution, and make the combined solutions alkaline to phenol red TS with ammonium hydroxide. Add 10 mL of Potassium Cyanide Solution. Immediately extract the solution with successive 5-mL portions of Dithizone Extraction Solution, draining off each extract into another separator, until the last portion of dithizone solution retains its green color. Shake the combined extracts for 30 s with 20 mL of 1 100 nitric acid, and discard the chloroform layer. Add exactly 4 mL of Ammonia-Cyanide Solution and 2 drops of Hydroxylamine Hydrochloride Solution to the acid solution. Add 10 mL of Standard Dithizone Solution, and shake the mixture for 30 s. Filter the chloroform layer through an acid-washed filter paper into a Nessler tube, and compare the color with that of a standard prepared as follows Add 0.25 mL of the Standard Lead Solution containing 10 p,g/mL of lead (Pb) ion, 4 mL of Ammonia-Cyanide Solution, and 2 drops of Hydroxylamine Hydrochloride Solution to 20 mL of 1 100 nitric acid, and shake for 30 s with 10 mL of Standard Dithizone Solution. Filter through an acid-washed filter paper into a Nessler tube. The color of the Sample Solution does not exceed that in the control. 

Preparation.1 This maroon-colored chelate is prepared from N,N -disalicylalethylenediamine and cobalt (II) chloride. It can bind oxygen reversibly (102 2Co) both in the solid state and in various solvents.2 Van Dort and Geursen3 used it as a homogeneous catalyst for the oxidation of phenols by molecular oxygen. In methanol solution the main products from phenols with a free para position are the p-benzoquinones (yields 15-80%). In chloroform solution radical-complex products are sometimes the main products. 

The yeast tRNA (Sigma) solution is prepared in the following manner lyophilized tRNA IS dissolved in water at 30 mg/mL, extracted twice with phenol and twice with phenol/chloroform, precipitated with ethanol, and resuspended in water as a 10 ixg/pL (OD measurement) stock solution stored in aliquots at -20°C... 

A mixture of B g (0.0356 mol) of p-(2.2-dichlorocyclopropyl)phenol, 11.2 g (0.2B mol) of sodium hydroxide pellets, 11 g of chloroform and 350 ml of acetone was prepared at 0°C. The cooling bath was removed, the mixture stirred for a minute and then heated on a steam bath to reflux temperature. The reaction mixture was stirred at reflux for three hours and then concentrated in vacuo. The residual gum was partitioned between dilute hydrochloric acid and ether, and the ether layer was separated, dried and concentrated in vacuo. The residual oil (14 g) was partitioned between dilute aqueous sodium bicarbonate and ether. The sodium bicarbonate solution was acidified with concentrated hydrochloric acid and extracted with ether. The ether solution was dried over anhydrous sodium sulfate and concentrated. The residue (9.5 g of yellow oil) was crystallized twice from hexane to give 6.0 g of 2-[p-(2,2-dlchlorocyclopropyDphenoxyl -2-methyl propionic acid in theformof apalecream[Pg.347]

After 2 h incubation of the prepared antibody beads with UV-crosslinked extract in a cold room, the beads are washed 4 x with 100 /A RIPA buffer (50 mMTris-HCl pH 7.5, 150 rnMNaCl, 1% NP-40, 0.5% sodium deoxycholate, and 0.1% SDS) and lx with genomic DNA lysis buffer (50 mM Tris, pH 7.4, 10 mM EDTA, 500 mM NaCl, 2.5 mM DTT, 0.5 mM spermidine, 1% Triton X-100). Approximately 300 /(I of PK solution (1 mg/ml proteinase K in genomic DNA lysis buffer and 0.2 U//A RNase inhibitor) is added to the total lysate previously kept on ice and the beads are then incubated at 37° for 30 min. Gently flick the tubes to resuspend the beads every 10 min during the incubation. After removal of the proteinase K solution, 300 /A of RNA extraction solution (4 M guanidine thiocyanate, 0.5% sarkosyl, and 25 mM sodium citrate, pH7) is added to the beads, incubated for 10 min and the supernatant is mixed with 30 fig yeast tRNA (as a carrier) and 30 fil of 3 M sodium acetate. The RNA solution is phenol-chloroform extracted, ethanol-precipitated, and the pellet washed once with 70% ethanol. The dry pellet is used for 1st strand cDNA synthesis, followed by PCR analysis. The removal of proteins... 

Cognate preparation. 2-Hydroxy-l-naphthaldehyde. Equip a 1-litre threenecked flask with a separatory funnel, a sealed mechanical stirrer and a double surface reflux condenser. Place 50 g of 2-naphthol and 150 ml of rectified spirit in the flask, start the stirrer and rapidly add a solution of 100 g of sodium hydroxide in 210ml of water. Heat the resulting solution to 70-80 °C on a water bath, and place 62 g (42 ml) of pure chloroform (CAUTION) in the separatory funnel. Introduce the chloroform dropwise until reaction commences (indicated by the formation of a deep blue colour), remove the water bath and continue the addition of the chloroform at such a rate that the mixture refluxes gently (about 1.5 hours). The sodium salt of the phenolic aldehyde separates near the end of the addition. Continue the stirring for a further 1 hour. Set the condenser for downward distillation (but... 

Cyclotriveratrylene synthesis is a poorly understood process, as with many reactions between phenols and aldehydes, and yields are as variable as the methods to prepare them a review lists fifteen different conditions that give between 21 and 89% yield. Despite this the compounds are worth preparing as they have an interesting affinity for buckminsterfullerene, C6o, and are cited in papers and patents that describe methods to isolate pure C6o from a mixture of fullerenes [50], It transpires that the threefold symmetry of cyclotriveratrylene is complementary to the threefold axis of C6o and that the two form very stable complexes in toluene as shown in Fig. 1.12, which precipitate leaving other fullerenes in solution. If the precipitate is isolated and taken up in chloroform the complex dissociates leaving cyclotriveratrylene in solution and precipitates C6o- The purity of the C6o treated in this way is significantly enriched and can approach 100%. At the time of this discovery fullerene research was very much in its infancy, and the material available was of variable purity, making the purification technique an important milestone in the history of fullerene chemistry. 

A high ECD response is also provided by 2,4-dinitrophenyl ethers, for which various methods of preparation were reported by Cohen et al. [63]. A 4-ml volume of acetone containing phenols (ca. 10 yjg), 0.1 ml of a saturated methanolic solution of sodium methanolate and 1 ml of l-fluoro-2,4-dinitrobenzene in acetone (1%, w/v) were refluxed in a 10-ml flask for 30 min. The reaction mixture was then added to 25 ml of sodium hydroxide solution (2.5%, w/v), diluted with a small volume of water and extracted with 25 ml of chloroform. After being dried with anhydrous sodium sulphate, the extract was carefully evaporated and the residue was dissolved in acetone and injected into the chromatograph. 

To isolate genomic DNA from E. coli, the cells are treated with lysozyme and then lysed by SDS in the presence of proteinase K. Proteinase K, which is active even in SDS solution, degrades proteins including nudeases. Cell debris, polysaccharides and unhydrolysed protein are removed by precipitation at room temperature with cetyltrimethylammonium bromide (CTAB). DNA is isolated from the supernatant by precipitation with alcohol. RNA can be removed from DNA preparations by incubation with DNase-free RNase. Further purification can be effected by a phenol/ chloroform/isoamyl alcohol (25 24 1) extraction, and/or by CsCl gradient centrifugation (see Sect. 4.3.4.2 ) to remove the remaining protein and RNA. 

Oxidations with peroxybenzoic acid are carried out in solutions in dichloromethane, chloroform, benzene, ether, or ethyl acetate at or below room temperature and include epoxidation of double bonds [295, 296, 297, 298, 299, 300, 301], oxidation of benzaldehydes to carboxylic acids or phenols [302], the Baeyer-Villiger reaction of ketones [303, 304, 305, 306, 307], and oxidation of sulfides to sulfoxides [308, 309]. Peroxybenzoic acid is also used for the anti hydroxylation of double bonds [310], the oxidation of pyrrolidines to pyrrolidones [377] and of pyrroles to succinimides [377], and the preparation of azoxy compounds from azo compounds [372]. 

Preparation. The reagent is prepared i n 81 % yield by the reaction of p-chloro-phenol in 1 N NaOH solution with thiophosgene in chloroform.1... 

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