Tetrabutylammonium sulphate

The method for analysing sediment involves extraction of organochlorine insecticides and polychlorobiphenyls with a mixture of acetone and hexane together with 1% aqueous ammonium chloride. The extracts are then concentrated for purification with concentrated sulphuric acid and aqueous sodium sulphite in the presence of tetrabutylammonium sulphate and finally gas chromatographic analysis is applied. 

Figure 9.3 shows the gas chromatogram obtained for a sulphur containing sediment sample before and after treatment with tetrabutylammonium sulphate-sodium sulphate. It is seen that the effects of sulphur and sulphur containing organic compounds in the sample are completely eliminated by this treatment. 

Separate phases by addition of 200 pL chloroform containing 10 pg/mL Folsch lipids and 200 pL 2.4 M HC1, 5 mM tetrabutylammonium sulphate. Vortex and centrifuge (1000, 5 min) to separate phases. 

For the analysis of atropine and its major acidic decomposition products, Kreilgard used 0.01 M tetrabutylammonium sulphate as pairing-ion in a mobile phase of acetonitrile - 0.05 M... 

The within- and between-bottle homogeneity was verified and the variances were compared with the method variance (assessed on the basis of replicate analyses of an extract). A 500 mg portion of the sediment was extracted in a Soxhlet apparatus with 120 mL of a mixture of n-hexane and acetone 90/10 (v/v) for 6 h. The extract was concentrated and taken into a volume of 1 mL iso-octane. The concentrated extract was eluted over 2 g deactivated silica (with 15% water) with 15 mL of petroleum ether. The eluate was concentrated to a volume of 1 mL and treated with 1 mL of a solution containing 34 g L tetrabutylammonium sulphate, and sodium sulphite and isopropanol for the removal of sulphur. The concentrated eluate was cleaned over a column packed with 1.5 g deactivated silica (with 5% water). An internal standard solution (CB 198) was added to the clean extract. The mixture was separated on an Ultra-2 column (length 50 m, internal diameter 0.2 mm, film thickness 0.33 mm. He carrier gas, 65 min gradient from 90 to 275°C) with electron capture detection. No significant difference in the variance of the between- and the within-bottle series and the analytical method itself Therefore, it was concluded that the material is homogeneous for CBs. 

Water insoluble tetrabutylammonium metaperiodate, which can be prepared from sodium metaperiodate and tetrabutylammonium hydrogen sulphate in aqueous solution, was found to be a useful reagent for the selective oxidation of sulphides in organic solvents . The reaction was generally carried out in boiling chloroform and gave dialkyl, alkyl aryl and diaryl sulphoxides in yields which are comparable with those reported for sodium metaperiodate in aqueous methanol solution (Table 4). In the case of diaryl sulphoxides, the yields decrease with prolonged reaction time. 

Fig. 5.5 Chromatogram ofchlor-prothixene hydrochloride CRS which contains 2.7 % ofthe f -isomer. (Column 4 x 120 mm hypersil BDS [3 pm]. Mobile phase 6.0 g potassium dihydrogen phosphate, 2.9 g sodium lauryl sulphate, 9.0 g tetrabutylammonium bromide 550 ml water, 50 ml methanol and400 ml acetonitrile, flow rate 1.5 ml/min and detection wavelength 254 nm.)...

Cotterill [222] has developed a procedure, discussed below, in which the herbicides are extracted from soil with saturated calcium hydroxide solution. After clean-up the residues are ethylated using iodoethane and tetrabutylammonium hydrogen sulphate as counter ion. Liquid-liquid partition and the use of a macroreticular resin column were compared as clean-up steps and the reaction conditions for optimum yield of ethyl ester were evaluated. 

The preparation of alkyl methyl ethers may be readily effected under PTC conditions from the alcohol, dimethyl sulphate and 50 per cent w/w aqueous sodium hydroxide, employing tetrabutylammonium hydrogen sulphate as catalyst.95 The usefulness of this procedure has been extended, and optimum conditions have been described for the alkylation of a range of aliphatic alcohols using, for example, 1-chlorobutane or benzyl chloride.96 The PTC preparative examples described in Expt 5.73 are for the methylation, allylation, but-2-enylation and benzylation of, for example, 2-hydroxymethyl-l,4-dioxaspiro[4.5]decane (Expt 5.63), and have been developed in the editors laboratories. These methods have also been applied to the alkylation of protected monosaccharide derivatives (p. 652). 

PTC methods for the oxidation of water-insoluble acid-sensitive alcohols have been described which use an aqueous sulphuric acid solution of potassium dichromate, dichloromethane and catalytic amounts of tetrabutylammonium hydrogen sulphate.103... 

Cognate preparation. Ethyl (E)-but-2-enoate255 (PTC procedure). A solution of triethyl phosphonoacetate (35 mmol) and acetaldehyde (35 mmol) in dichloromethane (5 ml) is added dropwise to a stirred two-phase system consisting of dichloromethane (35 ml), aqueous sodium hydroxide (20 ml, 50%) and tetrabutylammonium iodide (0.7 g) (1). The strongly exothermic reaction is complete in 15 minutes. The organic layer is separated, washed with water (5 ml), and dried with magnesium sulphate. Evaporation of the solvent and distillation of the residue affords the product, b.p. 51-52 °C/25mmHg, in 54 per cent yield. 

Benzylideneaniline (18.1 g, 0.1 mol) and tetrabutylammonium hydrogen sulphate (0.5 g, 1.35 mol) are dissolved in dichloromethane (100 ml) and a layer of 50 per cent aqueous sodium hydroxide introduced under this solution. Trimethylsulphonium iodide (20.4 g, 0.1 mol) is then added and the whole warmed at 50 °C with vigorous stirring for 2 hours, whereupon the originally undissolved sulphonium salt disappears. The mixture is poured on to ice, the organic phase separated, washed with water and dried. The solvent is evaporated and the residue distilled under reduced pressure to afford 1,2-diphenylaziridine (94%), b.p. 120°C/0.05mmHg. 

Dissolve 5.3 g (0.05 mol) of benzaldehyde (previously shaken with sodium hydrogen carbonate solution) and 0.25 g (0.67 mmol) of tetrabutylammonium iodide in 50 ml of dichloromethane. Place this solution in a 250-ml, three-necked round-bottomed flask equipped with an efficient sealed stirrer unit, a reflux condenser and a thermometer sited in a screw-capped adapter, and supported in an oil bath mounted on an electric hot plate. Introduce 50 ml of a 50 per cent (w/v) aqueous solution of sodium hydroxide, and then 10.2 g (0.05 mol) of finely powdered trimethylsulphonium iodide. Adjust the electric hot plate so that the oil bath is maintained at a constant temperature of 55 °C for 60 hours and during this period stir the reaction mixture rapidly (1). Pour the reaction mixture on to ice, separate the organic phase and extract the aqueous solution with one 20 ml portion of dichloromethane. Wash the combined organic phases successively with four 20 ml portions of water, two 10 ml portions of a saturated solution of sodium metabisulphite and finally two 20 ml portions of water. Dry the organic phase over anhydrous calcium sulphate, remove the dichloromethane on a rotary evaporator and distil the residue. Collect the phenyloxirane as a fraction having b.p. 191— 192 °C the yield is 4.7 g (78%). 

Iodobenzene (1.01 g, 4.9 mmol) was dissolved in dichloromethane (75 ml) and stirred vigorously with hypochlorite solution (200 ml of commercial laundry bleach adjusted to pH 8.2 and containing 200 mg of tetrabutylammonium hydrogen sulphate) at room temperature for 45 min. The reaction mixture was allowed to stand for 1 h then the precipitate was filtered to give crude iodylbenzene (0.69-0.94 g, 59-81%). Purification may be effected by crystallization from water or acetic acid. 

TBAH = tetrabutylammonium hydrogen sulphate d,l-190 P A ° - L-MenCH(Me)CH(NH2)COOH (119)... 

Consider a study, by HPLC, of the separation of three nucleotides (AMP, ADP and ATP), with a column of type RP-18. The mobile phase is a binary mixture of H2O — KH2PO4, 0.1 M (pH 6)/methanol (90/10). The compounds appear in the order ATP, ADP, AMP. If a solution of 4 mM tetrabutylammonium hydrogen sulphate is added to the mobile phase, the order of elution of these compounds is reversed (see Figure 3.15). 

Mobile phase Gradient. MeCN 10 mM pH 7.2 potassium phosphate buffer containing 5 mM tetrabutylammonium hydrogen sulphate at 25 75 for 20 min, then to 50 50 over 45 min, hold at 50 50 for 10 min. 

Fig. 8. Effect of imraunoaffinity chromatography on HPLC-fluorescence analysis of lAA in an extract from dwarf-1 Zea mays shoots. Sample A. acidic, diethylether extract B. as A but extract subjected to immunoaffinity chromatography. Column 250x5.0 mm i.d. 5 p,m ODS Hypersil. Mobile phase 25 rain, 25-75% gradient of methanol in 1% aqueous acetic acid. Flow rate 1 ml min. Detector fluorimeter, excitation 280 nm, emission 350 nm. Sample C. lAA-like peak from B. Column, flow rate and detector as A and B. Mobile phase 35% methanol in 50 mM phosphate buffer and 20 mM tetrabutylammonium hydrogen sulphate at pH 6.5 [93].

Fig. 11.1.4. Separation of uracil and 5-fluorouracil bases, nucleosides and nucleotides by reversed phase ion-pair HPLC. Chromatographic conditions column, Bondapak Cig (300 x 4 mm) mobile phase, (from 0-30 min) 0.1 mM tetrabutylammonium hydrogen sulphate (Cjg), 2.5 mM tetraethylammonium bromide (Cg) and 2% methanol in 2 mM sodium acetate, 1.5 mM phosphate buffer, pH 6.0 (Buffer A) (from 30-50 min) Buffer A-i-30 mM phosphate detection, UV at 254 nm. Peaks FU, fluorouracil FUR, fluorouracU riboside/ FUdR, fluorouracil deoxyriboside FUMP, fluorouridine 5 -monophosphate 5 dFUR, 5 -deoxyfluorouracil riboside FdUMP, deoxyfluorouri-dine monophosphate UDPG, uridine diphosphoglucose UDP, uridine diphosphate dUDP, deoxyuridine monophosphate UTP, uridine triphosphate. Reproduced from Au et al. (1982), with permission.

---