The reaction of phenol, 2-nitrophenol, thymol, 1-naphthol and 1-hydroxy-2-naphthoic acid with HCl-H2O2 was carried out in the presence and in the absence of ultrasound. In the presence of ultrasound phenol, 2-nitrophenol and thymol gave only the chlorinated products, while 1-naphthol and 1-hydroxy-2-naphthoic acid gave chlorinated quinones as the major products. The reactions with ultrasound were compared with those without ultrasound.

Substituted acetophenones react with N-bromosuccinimide (NBS) and p-toluenesulfonic acid (p-TsOH) in the presence of ultrasound in methanol at 35 +/- 2 degrees C to give alpha-bromoacetophenones in high yield. In the absence of ultrasound the reaction takes place at the boiling point of methanol (65 degrees C) and takes longer time. The reaction does not take place in the absence of p-TsOH thermally or sonically. However the reaction is possible under photochemical conditions in the absence of p-TsOH. The best solvent for the reaction was found to be methanol.

SynopsisFired clay membranes were prepared from montmorillonite clay and also by incorporating protein (lysozyme) and nylon (copolymer of 6-amino caproic acid) to clay followed by firing these membranes at different temperatures for different durations of time. Osmotic behaviors of the membranes were studied, and the results were correlated to the porosity determined by scanning electron microscope. Reverse osmosis parameters, namely, the reflection coefficient, solute permeability, and rejection coefficient, of the membranes were determined from osmosis experiments. Rejection coefficients as determined from reverse osmosis were compared with those obtained from osmosis experiments.

Recently, precise detection of VOCs in particular acetone, ammonia alcohol has attracted huge attention for industrial safety, monitoring of environment and human health. In this article we have reported for a polypyrrole nanotube (PPNT)‐based chemiresistive sensor for the selective detection of trace acetone vapour at room temperature (25 °C). Polypyrrole (PPy) nanoparticles with different morphologies, viz. nanotubes, nanowire, and globular were synthesized using methyl orange (MO), cetyltrimethyl ammonium bromide (CTAB), and pure polypyrrole as the growth template. The as synthesized powders were exploited to fabricate Taguchi‐type thick‐film sensors. The synthesized powders and fabricated sensors were characterized by multiple sophisticated techniques, such as, XRD, FTIR, Raman spectroscopy, SEM, EDS, UV‐VIS spectroscopy, optical non‐contact profilometry, and current‐Voltage (I‐V) measurement. It is observed that the PPNT sensor shows the highest response to trace acetone vapour with a lower detection limit of 500 ppb at room temperature (25 °C) and quick response (∼5.4 sec) and recovery (∼73.94 sec) times. Achieved enhanced sensing behaviour can be attributed to formation of hydrogen bond between acetone and PPy. Combined with room temperature sensing, good stability, repeatability, produce sensor may find application in various sensing fields.

The thermal decomposition reactions of some homoionic clay minerals, viz. vermiculite, in air in the temperature range 30°-l000°C by thermo-analytical methods are reported. The reaction kinetic of iso· thermal dehydration and dehydroxylation is found to obey first order reaction rate.