An Oxidation Study of Phthalimide-Derived Hydroxylactams

A systematic study of the oxidation of 3-hydroxy-2-substituted isoindolin-1-ones (hydroxylactams) and their conversion to the corresponding phthalimides was undertaken using three oxidants. Of special interest was the introduction of nickel peroxide (NiO2) as an oxidation system for hydroxylactams and comparison of its performance with the commonly used pyridinium chlorochromate (PCC) and iodoxybenzoic acid (IBX) reagents. Using a range of hydroxylactams, optimal conversions of these substrates to the corresponding imides was achieved with 50 equivalents of freshly prepared NiO2 in refluxing toluene over 5–32 h reaction times. By comparison, oxidations of the same substrates using PCC/silica gel (three equivalents) and IBX (three equivalents) required oxidation times of 1–3 h for full conversion but required lengthier purification. While nominal amounts (~25 mg) of substrate hydroxylactams were used to ascertain conversion, scale-up procedures using all three methods gave good to excellent isolated yields of imides.

Validated high performance thin layer chromatographic analysis of leaves and flower extracts of

is a significant therapeutic plant has a place with family apocynaceae contains in excess of 70 distinct sorts of chemotherapeutic agents and alkaloids which help in treating different illnesses. For the most part, it is known as Vincarosea, Ammocallisrosea and Lochnerarosea. There are numerous or more than 400 alkaloids present in plant, which are used as flavor, agrochemicals, pharmaceuticals, fragrance, ingredients, food addictives, and pesticides. To develop a validated high performance thin layer chromatographic method for the analysis of leaves and flower extracts of Sample solutions were applied onto the plates with automatic TLC sampler Linomat V (Camag, Muttenz, Switzerland) and were controlled by WinCATS software. Plates were developed in 10 x 10cm twin trough glass chamber (Camag, Muttenz, Switzerland). A CAMAG TLC scanner was used for scanning the TLC plates. Pre-coated silica gel aluminium plates 60F254. For vincristine, simultaneous estimation of vincristine was performed by HPTLC on a silica gel plate using toluene-methanol-diethylamine (8.75: 0.75: 0.5, v/v/v) as the mobile phase. The method was validated as per the ICH guidelines. The Rf value was found to be 0.76 for flower and 0.80 for leaves at 250 nm which shows the presence of vincristin in . In this research paper, a validated HPTLC Method has been developed for the analysis of leaves and flower extracts

Possibility of Advanced Modified-Silica-Based Porous Materials Utilisation in Water Adsorption Processes—A Comparative Study

Due to a high risk of power outages, a heat-driven adsorption chillers are gaining the attention. To increase the efficiency of the chiller, new adsorbents must be produced and examined. In this study, four newly developed silica–based porous materials were tested and compared with silica gel, an adsorber commonly paired with water. Extended sorption tests using mercury intrusion porosimetry, gas adsorption, and dynamic vapor sorption were performed. The morphology of the samples was determined using a scanning electron microscope. The thermal properties were defined using simultaneous thermal analysis and a laser flash method. Metal organic silica (MOS) nanocomposites analysed in this study had thermal properties similar to those of commonly used silica gel. MOS samples have a thermal diffusivity coefficient in the range of 0.17–0.25 mm2/s, whereas silica gel of about 0.2 mm2/s. The highest water adsorption capacity was measured for AFSMo-Cu and equal to 33–35%. For narrow porous silica gel mass uptake was equal about 25%. In the case of water adsorption, it was observed that the pore size of the sorbent is essential, and adsorbents with pore sizes higher than 5 nm, are most recommended in working pairs with water.

Expeditious Base-free Solid-State Reaction between Phenyl Boronates and Hydrogen Peroxide on Silica Gel

The conversion of phenyl boronates to phenol by hydrogen peroxide (H2O2) usually requires the base as the chemical assistant. In this work, we reported a base-free reaction between the phenyl...

Performance Testing and Analysis of Silica Gel-Water Adsorption Refrigerator

In recent years, adsorption refrigeration technology has attracted wide attention from experts and scholars at home and abroad due to its environmental friendliness and energy saving advantages. In order to study the effectiveness of adsorption refrigeration technology to recover low-grade energy, a silica gel-water adsorption refrigeration system was proposed, which can effectively utilize low-grade energy such as industrial waste heat. The structure and composition of the system are introduced. The operation performance of the unit is tested under different working conditions by orthogonal experimental method, and the experimental results are analyzed. The effects of hot water temperature and flow, chilled water temperature and flow on the refrigeration capacity and COP value of the system are obtained. The experimental results show that under the low-temperature heat source of 55-75°C, the cooling capacity of the system can reach 5.3-12 and the COP value can reach 0.36-0.56. Under the same hot water temperature difference, the cooling capacity and COP value of the system increase rapidly under the condition of changing the hot water temperature at low temperature, indicating that increasing the heat source temperature at low temperature has a greater impact on the system performance. Through the analysis of primary and secondary effects, it is concluded that the inlet temperature of hot water is the main factor affecting the refrigeration capacity and COP value of the system.

Sintering Bi2O3–B2O3–ZnO ternary low temperature glass by hydration device to solidify iodine containing silver-coated silica gel

A new glass solidification process aims at radioactive iodine waste was explored in order to reduce the possible harm to environment. Samples with different iodine content in silver-coated silica gel were pretreated by hydration device at 300 °C and then sintered at relatively low temperatures (500, 550 and 600 °C). XRD results show that AgI is mainly chemically fixed in the glass network with some AgI particles being physically wrapped by the glass. Moreover, as the sintering temperature reached to 550 °C, B element crystallized. SEM-EDS results show that Ag and I elements are enriched, while the other elements are evenly distributed. AFM results showed that the sample surface becomes rougher as the iodine content increases in the silver coated silica gel. The FT-IR results show that the structure of the sintered sample is mainly composed of [BiO3], [BiO6] and [BO3]. This study provides a new sintering method by hydration device for the treatment of radioactive iodine waste.