P-toluenesulfonic Acid Solution Research Articles

Characterization of polyaniline films electrodeposited on mild steel in aqueous p-toluenesulfonic acid solution

Aqueous p-toluenesulfonic acid solution is used to electrosynthesize a polyaniline (PANi) film on mild steel. Polarization of the substrate in this medium leads to passivation of the surface mainly via the formation of an iron oxide layer. When aniline is added to the solution, electropolymerization is not hindered and a dark green deposit is obtained in high yield (80%). Spectrochemical techniques (IR, XPS and UV) and mass determination (SEC and MALDI) indicate that it has the same properties as reported for PANi. Evaluation of the anticorrosion performances of the film shows that the corrosion current is divided nearly by ten, suggesting that this polymer coating could be used for corrosion protection.

Voltammetric Studies of Transport of Thallium(I) Counterions in Solutions of Polyelectrolytes in Mixed Solvents

Transport of thallium(I) counterions was studied in solutions of poly(styrenesulfonic acid), PSSA, in mixed solvents by steady-state voltammetry at mercury microelectrodes. The diffusion coefficient values of TlI obtained in polyelectrolyte solutions were compared to those from solutions of p-toluenesulfonic acid, p-TSA, the simple acid, monomer analogue of PSSA. The dependence of the transport of TlI counterions on the dielectric constant, ε, of the solvent was investigated for such solvents as ethanol−, methanol−, and 1,4-dioxane−water mixtures over a wide range of ε-values. The diffusion coefficient of thallium(I) counterions in PSSA normalized by the diffusion coefficient in solution of the simple acid, p-TSA, was found to change proportionally to the change in the dielectric constant value of the solvent. This dependence is close to that predicted by Manning's theory. The results were obtained over a wide range of concentrations of counterions and over a wide range of concentrations of various supporting electrolytes.

Alkylation of phenol with cyclohexene catalysed by cationic ion-exchange resins and acid-treated clay: O- versus C-alkylation

Alkylation of phenol with cyclohexene was carried out in the presence of different cation-exchangers and acid-treated clay (Filtrol-24) as catalysts in the temperature range 45–120°C. The role of homogeneous catalysts such as 50% aqueous solution of p-toluenesulfonic acid (PTSA) and 98% H 2SO 4 was also assessed. This reaction is unique in that a substantial amount of cyclohexyl phenyl ether is formed at lower temperature, which may well have good perfumery value. Amberlyst-15 was the best catalyst so far as the activity was concerned. Selective O-alkylation can be obtained in the presence of Filtrol-24 as catalyst in the temperature range 45–60°C. The suitability of cyclohexanol as the alkylating agent was assessed. It can be used for C-alkylation in the temperature range 180–250°C in the presence of Filtrol-24 as catalyst.

Analysis of sub-microgram quantities of nucleotides by fast atom bombardment mass spectrometry.

Nucleotides of the structure P1,Pn-di(adenosine-5')-n-phosphate (n = di- through penta-) in the form of salts, and P1,P4-di(guanosine-5')tetraphosphate sodium salt have been analyzed by fast atom bombardment (FAB) mass spectrometry. A 0.2 molar solution of p-toluenesulfonic acid in glycerol has been evaluated as a matrix. In this matrix, the metal ions of the nucleotide salts are readily exchanged for protons, resulting in a simple spectrum with only one peak in the molecular ion region corresponding to the free phosphoric acid of the nucleotide plus or minus a proton (positive or negative mode), instead of the multiplicity of peaks arising from a series of metal and matrix adduct ions found with glycerol as matrix. The detection limit for analytes using this matrix is improved by a factor of ten compared to glycerol alone. It appears that the high acidity and the surfactant properties of p-toluenesulfonic acid both contribute to this result. Useful spectra are obtained from 250 ng of each of the above mentioned nucleotides, with the detection limit being somewhat lower in the positive mode. However, both positive and negative FAB spectra are useful and the results are complementary.

Measurement of the acidity function H0 of sulfo cation exchangers by the indicator method

1. A method of the measurement of the acidity function H0 of sulfo cation exchangers was proposed. It was based on their absorption of an indicator base from an aqueous solution taking into account the activity coefficient of its unionized form (fB) in the phase of the sulfo cation exchanger. This is measured in an aqueous solution of p-toluenesulfonic acid with the same molar ratio of the sulfo groups to water as in the swollen sulfo cation exchanger. 2. The fB values of o-nitroaniline in aqueous solutions of p-toluenesulfonic acid (up to 53%) were measured at 25°C. 3. The H0 values of styrene-divinylbenzene sulfo cation exchangers of the gel type KRS-1, KRS-3, KRS-6, KRS-10, and KRS-12 and the large-pore types KU-23-15/100 and KU-23-30/ 100 were measured at 25°C.

Extreme sensitivity of grandisal to acids

Attempted purification of synthetic racemic grandisal1 by silica gel chromatography resulted in severe decomposition. The nature of this reaction was studied on silica gel and in an ether solution ofp-toluenesulfonic acid. The same products resulted from both reaction systems, although in different ratios. Five racemic, rearrangement products were isolated by preparative GC and identified as follows: (1RS, 3SR, 6RS)-1-methyl-5-methylenebicyclo[4.2.0]octan-3-ol (4); (1RS, 3RS, 6RS)-1-methyl-5-methylenebicyclo[4.2.0]octan-3-ol (5); (1RS,3RS,6RS)-1,5-dimethylbicyclo[4.2.0]oct-4-en-3-ol (6); (1RS,3SR,6RS)-1,5-dimethylbicyclo[4.2.0]oct-4-en-3-ol(7); and 3-methyl-7-methylenecyclooct-3-en-l-ol (8). The stereochemical assignments are based on our proposed mechanism, which also accounts for all products observed. The racemic bicyclic enone (3) was a by-product of grandisol (2) oxidation.

Effect of solvent on the hydration of 2-methyl-propene in solutions of p-toluenesulfonic acid and poly(styrenesulfonic acid)

Results are reported of a kinetic study on the hydration of 2-methylpropene at 25.0 °C in solutions of p-toluenesulfonic acid and poly-(styrenesulfonic acid) in mixtures of 1,4-dioxane or sulfolane and water. Both cosolvents have a large influence on the rate of hydration. For sulfolane the rates are higher than for 1,4-dioxane, in spite of the higher solubility of the alkene in 1,4-dioxane/water mixtures. For the reactions catalyzed by p-toluenesulfonic acid, the variation of the pseudo first-order rate constant as a function of the solvent composition is explained in terms of the Hammett acidity function and an examination of the influence of the solvent on the initial- and transition-states of the reaction. Contrary to the rates of the reactions catalyzed by p-toluenesulfonic acid, the rates per equivalent of acid groups are independent of the acid concentration for the reactions catalyzed by poly(styrenesulfonic acid). This is explained by assuming that solutions of poly(styrenesulfonic acid) are divided into an ordered polymer-rich pseudo-phase and a highly disordered pseudo-phase in which the polymer concentration is very low. It appears that for the same overall mol fraction of the cosolvent, the amount of cosolvent in the ordered pseudo-phase is considerably higher for the rather polar sulfolane than for the almost non-polar 1,4-dioxane. The results of this study will give insight into the influence of the solvent composition on the catalytic activity of sulfonated polystyrene/ divinylbenzene-type cation exchange resins, which are used as catalysts for the hydration of lower alkenes on an industrial scale.

Thermochemical comparisons of homogeneous and heterogeneous acids and bases. 1. Sulfonic acid solutions and resins as prototype Broensted acids

Heats of ionization by thermometric titration for a series of bases (or acids) can be used to compare solid acids (or bases) with liquid analogues bearing the same functionalities in homogeneous solutions. The method is demonstrated for Broensted acids by reacting a series of substituted nitrogen bases with solutions of p-toluenesulfonic acid (PTSA) in acetonitrile and with suspensions of the microporous polymeric arylsulfonic acid resin-Dowex 50W-X8 in the same solvent. Under well-controlled anhydrous conditions there is a good correlation (r = 0.992) between the heats of reaction of the bases with the homogeneous and heterogeneous acid systems, but the homogeneous system gives a more exothermic interaction by 3-4 kcal mol/sup -1/ for a series of 29 substituted pyrimidines, anilines, and some other amines. This difference may be attributed to homohydrogen bonding interactions between excess acid and sulfonate anion sites which are more restricted geometrically in the resin than in solution. Other factors which affect the enthalpy change for the acid-base interaction are the acid/base ratio, the water content of the sulfonic acid, the solvent, and the resin structure (e.g., microporous vs. macroporous). Steric hindrance in the base does not differentiate solid from homogeneous acid. In addition to the use ofmore » titration calorimetry, heats of immersion are reported for the Dowex-arylsulfonic acid resins and the Nafion-perfluorinated sulfonic acid resin in a series of basic liquids. The results are compared with each other and with those from a previous study of several varieties of coal.« less

Chromatographic Analysis of Chlorpheniramine, Pyrilamine, and Methapyrilene in Combination

A partition chromatographic method is presented for the separation and quantitation of chlorpheniramine, methapyrilene, and pyrilamine in combination.A solution of p-toluenesulfonic acid and potassium chloride on a column of diatomaceous earth is used to effect the separation.The isolated chlorpheniramine is determined by UV spectrophotometry.The methapyrilene and pyrilamine are separated and determined by GLC.

Removal of vanadium from petroleum and petroleum products with aqueous solutions of sulfo acids

1. It was shown that it is possible to remove vanadium from petroleums and petroleum products with aqueous solutions of p-toluenesulfonic acid, o-sulfobenzoic acid, and sulfanilic acid. 2. Vanadium is extracted best from those petroleums and petroleum products in which the vanadium-porphyrin complex is not present.

Evaluation of simple precipitation test for systemic lupus erythematosus.

An unusual precipitate observed during the determination of serum cholesterol in a patient who later developed disseminated lupus erythematosus led to the elaboration of a test for this disease. The test reagent is a 12 % solution of p-toluenesulfonic acid in glacial acetic acid. The test consists in adding 0.1 ml. of serum or plasma to 2 ml. of the reagent. No precipitate appeared when this test was applied in 65 out of 66 healthy people; in one, a light precipitate appeared and persisted for 20 minutes, but redissolved on shaking. Applied in 30 patients in various stages of systemic lupus erythematosus, the test gave precipitates, the amount and character of which paralleled the severity of the disease. In 12 of the 13 acutely ill patients there was a heavy precipitate with this test. When this appeared as a glassy gel that resisted rubbing and shaking it was graded 4+. Altogether 760 tests were done on 311 subjects. Very few false-positive results were found. The test seems to be of value in the differential diagnosis of systemic lupus erythematosus and to afford a measure of the severity of the disease.