Densities, Viscosities and Excess Properties for Dimethyl Sulfoxide with Diethylene Glycol and Methyldiethanolamine at Different Temperatures

Densities and viscosities of the binary systems dimethylsulfoxide with diethylene glycol and methyldiethanolamine were measured at temperatures ranging from 293.15 to 313.15 K, at atmospheric pressure and over the entire composition range. The experimental density data was correlated as a function of composition using Belda’s and Herraez’s equations, and as a function of temperature and composition using the models of Emmerling et al. and Gonzalez-Olmos-Iglesias. The viscosity results were fitted to the Grunberg-Nissan, Heric-Brewer, Wilson, Noda, and Ishida and Eyring-NRTL equations. The values of viscosity deviation (), excess molar volume (VE), partial molar volumes ( and ) and apparent molar volume ( and ) were determined. The excess functions of the binary systems were fitted to the polynomial equations. The values of thermodynamic functions of activation of viscous flow were calculated and discussed.

Oxidative Damage Induced by Phototoxic Pheophorbide a 17-Diethylene Glycol Ester Encapsulated in PLGA Nanoparticles

Pheophorbide a 17-diethylene glycol ester (XL-8), is a promising high-active derivative of known photosensitizer chlorin e6 used in photodynamic therapy. However, high lipophilicity and poor tumor accumulation limit XL-8 therapeutic application. We developed a novel XL-8 loaded with poly(D,L-lactide-co-glycolide) nanoparticles using the single emulsion-solvent evaporation method. The nanoparticles possessed high XL-8 loading content (4.6%) and encapsulation efficiency (87.7%) and a small size (182 ± 19 nm), and negative surface charge (−22.2 ± 3.8 mV) contributed to a specific intracellular accumulation. Sustained biphasic XL-8 release from nanoparticles enhanced the photosensitizer photostability upon irradiation that could potentially reduce the quantity of the drug applied. Additionally, the encapsulation of XL-8 in the polymer matrix preserved phototoxic activity of the payload. The nanoparticles displayed enhanced cellular internalization. Flow cytometry and confocal laser-scanning microscopy studies revealed rapid XL-8 loaded nanoparticles distribution throughout the cell and initiation of DNA damage, glutathione depletion, and lipid peroxidation via reactive oxygen species formation. The novel nanoformulated XL-8 simultaneously revealed a significant phototoxicity accompanied with enhanced photostability, in contrast with traditional photosensitizers, and demonstrated a great potential for further in vivo studies.

Evaluation of the Diethylene Glycol Regeneration rate in Gas Fields Based on Indirect Measurements

Gas dehydration in the field is a mandatory procedure before long-distance transportation. In Russia, gas is dried by absorption using diethylene glycol (DEG). Upon absorbing moisture from the raw gas, DEG is regenerated and recycled to dehydration, the quality of which largely depends on the regeneration rate. This indicator is not measured directly at the dehydration plant, and regeneration is controlled discretely based on the periodic laboratory analysis results. The paper describes a virtual analyzer determining the DEG concentration in a real-time mode based on the temperature and DEG consumption measurement results. The regression mathematical model underlying the virtual analyzer has been built based on experimental data obtained at the Yamburg gas condensate field. As part of the gas treatment plant APCS, a virtual analyzer improves the treatment efficiency and reduces the DEG consumption.

The syntheses of poly (diethylene glycol adipate) in low-intensity ultrasound

Poly (diethylene glycol adipate) is an important product of chemical technology. Several grades of polyesters (P-9, P-9A) are produced in the industry, in which poly(diethylene glycol adipate) is the main component. These composites are used in production of binders of mixed rocket solid fuels, as well as consumer goods. Poly(diethylene glycol adipate) is obtained by polycondensation of diethylene glycol and adipic acid. Usually, the polycondensation is carried out using catalysts. The use of catalysts complicates this process: requires further purification process or in solvent free system might slow reaction rate due to the limiting diffusion between reactants and mass transfer limitations. Therefore, it was proposed to use low-intensity ultrasound, which allows to influence the kinetics of the process without complicating the system. In this work, the reaction of polycondensation of diethylene glycol and adipic acid in low-intensity ultrasound was studied. The results of applying low-intensity ultrasound to the preparation of poly(diethylene glycol adipate) showed an increase in the reaction rate of the formation of a high-molecular compound and a change in the thermal regime. Application of low-intensity ultrasound provides synchronization of vibration and rotation of self-organizing dissipative structures, which leads to the decrease in energy consumption for mass transfer, thereby increasing the reaction rate. The low-intensity ultrasound demonstrated to be an effective method to intensify the polycondensation reaction.

FIRE SAFETY OF HEAT-TRANSFER AGENTS FOR HEAT GENERATORS

Рассмотрены свойства двух групп теплоносителей, используемых для понижения рабочей температуры и для повышения рабочей температуры. В первую группу теплоносителей включены: этиленгликоль, диэтиленгликоль, триэтиленгликоль, пропиленгликоль, глицерин. Вторую группу теплоносителей составляют: дифенильная смесь, масло АМТ-300, масло ТЛВ-330, мобильтерм-600, дикумилметан, дитолилметан, тетрахлордифенил, тетракрезилсиликат, нафталин, тройная нафталиновая смесь, нитрит-нитратная смесь. Приводятся физико-химические и пожароопасные свойства названных теплоносителей, а также перечень профилактических противопожарных мероприятий и средств пожаротушения. There are considered the properties of two groups of heat-transfer agents used to reduce the operating temperature and to increase the operating temperature. The following substances are included in the first group of heat-transfer agents: ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin. The following substances are included in the second group of heat-transfer agents: diphenyl mixture, AMT-300 oil, TLV-330 oil, mobileterm-600, dicumylmethane, ditolylmethane, tetrachlorodiphenyl, tetracresyl silicate, naphthalene, triple naphthalene mixture, nitrite-nitrate mixture. There are cited the physicochemical and fire hazardous properties of the mentioned heat-transfer agents, as well as the list of preventive fire-fighting measures and fire-extinguishing facilities.