scholarly journals Polymers with regular alternation of 1,7-bis[(dimethyl)silylmethylene]-m-carborane and diorganosiloxane units

2019 ◽  
Vol 488 (4) ◽  
pp. 383-385
Author(s):  
B. A. Izmaylov ◽  
V. A. Vasnev ◽  
G. D. Markova
Keyword(s):  
Organic Solvents ◽  
Amorphous Polymers ◽  
High Thermostability ◽  
Regular Alternation

New high-thermostable carboranylmethyl-containing diorganosiloxane polymers have been obtained by polycondensation of equimolar amounts of 1.7-bis[hydroxy(dimethyl)silylmethylene]-m-carborane with bis(dimethylamino)diorganosilanes. It was shown, that in the case of replacement of 24 to 33 mol. % of dimethylsiloxane units with methylphenylsiloxane or diphenylsiloxane units with bulk phenyl groups, only amorphous polymers are formed. The polymers are highly soluble in organic solvents and have high thermostability.

Supercritical Solvent Impregnation in Controlled-Release Drugs

2010 ◽  
Vol 152-153 ◽  
pp. 1462-1465
Author(s):  
Zhen Tian ◽  
Nai Ci Bing ◽  
Ye Zhang ◽  
Ling Ling Wang ◽  
Wei Qiao
Keyword(s):  
Controlled Release ◽  
Organic Solvents ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Elevated Temperatures ◽  
Amorphous Polymers ◽  
Bioactive Molecules ◽  
Supercritical Solvent ◽  
Supercritical Fluid Technology ◽  
Toxic Organic Solvents

In the field of pharmaceutical industry, the controlled-release drugs have received considerable attention in the last years. Impregnation using supercritical fluid technology has already proven its feasibility in the preparation of controlled release systems. The use of supercritical fluids such as supercritical CO2 has provided a ‘clean’ and effective alternative to traditional methods of drug releasing and polymer processes. In particular, scCO2 has a number of unique properties that make it possible to process both bioactive molecules and amorphous polymers without using toxic organic solvents or elevated temperatures. A high purity product, free of residual solvents is obtained, since no organic solvents are involved in the impregnation process. Here, we review the advantages of supercritical fluid and the preparation of controlled-release drugs by supercritical solvent impregnation.

UNTERSUCHUNGEN ÜBER DIE EXTRAKTION DES ROTEN KOBER-FARBSTOFFS DURCH ORGANISCHE LÖSUNGSMITTEL ZUR ÖSTROGENBESTIMMUNG IM HARN

1960 ◽  
Vol XXXV (I) ◽  
pp. 34-48 ◽  
Author(s):  
Gerd Ittrich
Keyword(s):  
Menstrual Cycle ◽  
Organic Solvents ◽  
Urine Sample ◽  
Phenol Derivatives ◽  
Organische Lösungsmittel ◽  
Colour Complex

ABSTRACT A series of organic solvents and phenol derivatives have been examined for the extraction of the pink Kober-colour complex. Optimal results could be achieved for fluorimetry by a solution of 2 % (w/v) p-nitrophenol and 1 % (v/v) ethanol in acetylenetetrabromide, when the green mercury line (546 mμ was used as primary light. The sensitivity, stability and specificity have been improved, compared with the previously described reaction. By changing the sequence of purification steps and by reducing the volume of the urine sample (5 ml) the method for the determination of total oestrogens has been simplified. Approximately 10 determinations can be done within 3–4 hours by one person. Recovery experiments and comparative determinations with a previously described method have been carried out. The excretion of total oestrogens in a complete menstrual cycle is determined with the described method.

Imidazole Promoted Efficient Anomerization of β-D-Glucose Pentaacetate in Organic Solutions and Solid State

2019 ◽  
Author(s):  
Meifeng Wang ◽  
Liyin Zhang ◽  
Yiqun Li ◽  
Liuqun Gu
Keyword(s):  
Solid State ◽  
Organic Solvents ◽  
Room Temperature ◽  
Materials Design ◽  
The Future ◽  
Organic Solutions ◽  
Glucose Pentaacetate

<p></p>Anomerization of glycosides were rarely performed under basic condition due to lack of efficiency. Here an imidazole promoted anomerization of β-D-glucose pentaacetate was developed; and reaction could proceed in both organic solvents and solid state at room temperature. Although mechanism is not yet clear, this unprecedent mild anomerization in solid state may open a new promising way for stereoseletive anomerization of broad glucosides and materials design in the future..

Evaluation of exposure by organic and inorganic substances for identifying growing risk groups

2020 ◽  
pp. 685-686
Author(s):  
L. V. Lukovnikova ◽  
K. I. Stosman ◽  
E. E. Lesiovskaya
Keyword(s):  
Organic Solvents ◽  
Risk Groups ◽  
Blood Levels ◽  
Inorganic Substances ◽  
Cortisol Levels

Working in contact with nitroglycerine, TNT, RDX, oxygenatom, organic solvents, recorded elevated levels of cortisol in the blood. In contact with metals, their blood levels and cortisol levels did not differ from the average values of the professionally employed population.

Competitive adsorption of organic solvents using modified and unmodified calcium bentonite clay mineral

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Organic Solvents ◽  
Competitive Adsorption ◽  
Correlation Factor ◽  
Isotherm Model ◽  
Isotherm Models ◽  
High Concentration ◽  
Dual Purpose ◽  
Calcium Bentonite

Dodecyltrimethylammonium bromide (DTAB)–modified and unmodified calcium bentonite were both used for the competitive adsorption of aromatics (xylene, ethylbenzene and toluene) and petroleum products (gasoline, dual purpose kerosene and diesel) from their aqueous solution. Infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurement were performed in order to evaluate the performance of the adsorbents. The Foster swelling index and adsorption capacity of the DTAB modified calcium bentonite in the organic solvents follow the trend: xylene &gt; ethylbenzene &gt; toluene &gt; gasoline &gt; dual purpose kerosene (DPK) &gt; diesel &gt; water. However, the adsorption capacity of the adsorbent in diesel outweighed the adsorption capacity in DPK at high concentration of DTAB indicating that diesel has higher affinity for high DTAB concentration than DPK. The percentage removal of the solvent is directly proportional to the concentration of DTAB used in modifying the bentonite as well as the contact time between the adsorbent and the solvent, hence modified calcium bentonite adsorbed a higher percentage of organic solvents than the unmodified calcium bentonite. The adsorption characteristics of both adsorbents improved remarkably after proper agitation of the organic solvents, the unmodified calcium bentonite however adsorbed more water than the modified bentonite. Data obtained from adsorption isotherm models confirms that Freundlich adsorption isotherm model was favored more than Langmuir adsorption isotherm model with the correlation factor (R2) of the former tending more towards unity. The adsorption of ethylbenzene using DTAB modified and unmodified calcium bentonites follow a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves both the adsorbent and the organic solvent.

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