The evaluation of time variation global warming effects, TWPA and CWP, for CFC alternatives

Evaluations methods of global warming are presented by considering the direct warming effect of chemical compounds and of decomposed compounds, warming effect due to the formation of troposphere ozone, and the cooling effect due to the decomposition of stratosphere ozone. It is easy to take account the stabilization of global warming gases concentration in the atmosphere, as those methods can conduct the time variations analysis. The methods are named Total Warming Prediction Analysis (TWPA) and Composite Warming Potential (CWP). The evaluation of Mobile Air Conditioning refrigerant is presented as an example of application of our method.     

Modified Silica Sol Coatings for Water-Repellent Textiles

The preparation of water repellent textiles by coating with different modified silica sols has been investigated. For this, pure and with 3-glycidoxypropyl triethoxysilane co-condensed silica sols were modified by three types of additives: alkyltrialkoxysilanes, polysiloxane derivatives and a fluorine containing silane. Hydrophobic properties of the coated fabrics of polyamide and of polyester mixed with cotton were determined using contact angle measurements. The hydrophobicity increases with increasing concentration of the alkylsilane additive in the silica sol and the length of the alkyl chain but with high additive concentrations plateau values in hydrophobicity were reached. Analogously textile coatings with high hydrophobicity were gained using hydrophobic polysiloxane or fluorine containing silicon compounds. The comparison of the different variants reveals that high wash-out stabilities were reached only by silica sols containing fluorine compoundsand hexadecylsilane additives. Therefore long-chain alkyltrialkoxysilane compounds could be used as substitutes for fluorine compounds for the surface modification of textiles in some practical applications.     

Fluorine–proton correlation from isolated trifluoromethyl groups using unresolved J‐couplings

Fluorine‐containing compounds are rare in biological systems, so fluorine NMR spectroscopy can selectively detect and quantify fluorinated xenobiotics in crude biological extracts. The high sensitivity of fluorine NMR allows the detection of compounds containing isolated trifluoromethyl groups at nanogramme levels. However, it only provides limited structural information about trifluoromethyl‐containing compounds owing to the difficulty of interpreting fluorine chemical shifts and the low sensitivity of HOESY experiments used to correlate fluorine nuclei with protons in the same compound. This paper demonstrates that long‐range fluorine–proton J‐couplings can be used to correlate isolated trifluoromethyl groups with nearby protons with significantly higher sensitivity than HOESY. Fluorine‐observe fluorine–proton HMQC can even give correlations when the fluorine–proton J‐couplings are less than the observed fluorine resonance linewidth, so it provides a useful alternative source of structural information about fluorinated xenobiotics. Copyright © 2012 John Wiley & Sons, Ltd.     

Evaluation of carbon dioxide equivalent values for greenhouse gases: CEWN as a new indicator replacing GWP

A new indicator, the CEWN (Carbon Dioxide Equivalent Warming Number), is proposed as an alternative to the GWP (Global Warming Potential). CEWN is a metric where the global warming by the emission of gases is compared unifying the removal rate of each gas from the atmosphere, using carbon dioxide as a reference. To comply with the basket system of the Kyoto Protocol, GWP is used with a 100-year time horizon, making it unsatisfactory for the evaluation of long-lived compounds. As the removal rate from the atmosphere depends on the lifetime, the CEWN presents a fair assessment of the relative global warming.     

Some new approaches to modifying aromatic and heteroaromatic compounds by means of fluorine-containing substituents

Modification of physiologically active substances by means of fluorine atoms or fluoroalkyl groups is known in numerous cases to lead to compounds with a markedly higher activity. The optimum change in the properties is considered to be achieved by inserting 1-3 fluorine atoms into the molecule. Therefore modifications of compounds by such groups as CHF₂, CF₃, CH₂F are most frequently used in synthesis of fluorine-containing pharmaceutical and agricultural chemicals.

At the same time, the data obtained in recent years indicate the existence of some others regularities. Thus, in a number of cases highly active drugs have been revealed among highly fluorinated substances containing polar groups of atoms in the molecule. The physiological activity of fluorine-containing compounds seems to be determined not so much by the degree of fluorination as by the relationship between the hydrophobic and the hydrophilic properties. This conclusion is quite justified, since it is the compound's lipophilic-hydrophilic balance that determines its transport in biosystems and the possibility of the interaction with the lipoprotein sites of biomembranes. Moreover, compounds with a heightened fluorine con-     

Stereocontrolled Synthesis of Functionalized Azaheterocycles from Carbocycles through Oxidative Ring Opening/Reductive Ring Closing Protocols

Fluorine‐containing organic scaffolds are of significant interest in medicinal chemistry. The incorporation of fluorine into biomolecules can lead to remarkable changes in their physical, chemical, and biological properties. There are already many drugs on the market, which contain at least one fluorine atom. Saturated functionalized azaheterocycles as bioactive substances have gained increasing attention in pharmaceutical chemistry. Due to the high biorelevance of organofluorine molecules and the importance of N‐heterocyclic compounds, selective stereocontrolled procedures to the access of new fluorine‐containing saturated N‐heterocycles are considered to be a hot research topic. This account summarizes the synthesis of functionalized and fluorine‐containing saturated azaheterocycles starting from functionalized cycloalkenes and based on oxidative ring cleavage of diol intermediates followed by ring expansion with reductive amination.     

Separation of rare-earth elements and thorium in sorption conversion of phosphate rare-earth concentrate produced in nitric acid processing of Khibiny apatite concentrate

It is shown that REEs and thorium can be separated directly in the course of a sorption conversion of the phosphate rare-earth concentrate precipitated in nitric acid processing of the Khibiny apatite concentrate by introduction of compounds containing fluoride ions into the nitric acid solution used in the process. Under the optimal conditions, REEs are quantitatively adsorbed by the sulfo cation exchanger, whereas thorium mostly remains together with phosphorus and fluorine in the mother pulp. The influence exerted by the composition of compounds containing fluoride ions and process conditions on the separation efficiency of REEs and thorium. The suggested approach rules out formation of burial-requiring radioactive wastes with increased content of thorium.     

Fluorine in health care: Organofluorine containing blockbuster drugs

Organic fluorine compounds have had a profound impact on the development of bioactives for the modern pharmaceuticals market. It is estimated that up to 20% of pharmaceuticals prescribed or administered in the clinic contain a fluorine atom and 30% of the leading 30 blockbuster drugs by sales contain a fluorine. In this Highlight review, the top 10 fluorine containing pharmaceuticals (by US Sales in 2008) are highlighted. By this measure, these are currently the most significant fluorinated compounds impacting on health care. They embrace statins (Lipitor, Crestor, Vytorin, Zetia/Ezetimibe), anti-inflammatories (fluticasone propionate, Celebrex), antacids (Prevacid), antidepressants (Lexapro), neuroleptics (Risperdal) and antibiotics (Levaquin). In each case the structures and modes of action of these important drugs compounds are reviewed and representative synthetic routes are highlighted.     

Fluorine containing bioactive heterocycles. Part II. Synthesis of some new fluorine containing arylglyoxals,their hydrates and 1,5-disubstituted hydantoins

Eight new fluorine containing arylglyoxals have been synthesized by the oxidation of the active methyl group of fluorinated acetophenones by selenium dioxide in dioxan-water medium. The corresponding hydrates were obtained by dissolving arylglyoxals in minimum amounts of benzene and adding hot water. Seventeen new fluorine containing 1,5-disubstituted hydantoins were subsequently prepared by the condensation of these arylglyoxals with arylureas in ethanol and characterized by ir, pmr and mass spectral studies. Representative compounds have been screened for their possible anticonvulsant and analgesic activities. None of the compounds show significant analgesic acitivity.     

含氟新农药的构效关系研究Ⅰ.经典QSAR分析

为了能更深入地认识含氟新化合物作为农药的生物活性和其结构间的关系,建立有意义的构效关系模型,我们用经典QSAR(定量构效关系)方法研究了三十三个含氟化合物的两种不同的生物活性与结构的关系,其对抗黄瓜疫病活性模型有很好的解释能力和预测能力,并根据这个模型设计了一些新的活性结构.而对抑制西瓜白绢病的活性数据的处理未能获得理想模型.通过这一工作确立了先应用聚类等定性分析方法,再用多元统计分析方法作更深入研究的QSAR研究模式.     

Thermal analyses of home-made zeolite by DSC and TG

Volatile organic compounds (VOCs) and greenhouse gases are the main factors involved in pollution control and global warming. Various treatment methods involving incineration, adsorption, etc., have been employed to reduce VOCs and greenhouse gases concentration in the operating environment and atmosphere. Activated carbon, zeolite, silica gel, and alumina have been broadly used to adsorb pollutants in various industrial applications. Based on the promising effect of adsorption, we analyzed and identified the thermal phenomena of home-made zeolite using various instruments. The endothermic reaction under 100?°C of home-made zeolite was identified as steam adsorption, which is an important discovery. The optimal adsorption temperatures of home-made zeolite have been determined at 200?C550?°C.     

氟代有机硅化合物的合成新方法

本工作利用CuCl/HOC₂H₄NH₂催化剂,将1,2-二溴四氟乙烷与烯基有机硅化合物进行加威反应,制备了一系列新的含氟有机硅化合物,并进行了分析鉴定。对影响反应的诸因素做了初步探讨。     

Effect of lateral substitution by fluorine and bromine atoms in ferroelectric liquid crystalline materials containing a 2-alkoxypropanoate unit

Two homologous series of ferroelectric liquid crystalline compounds with 2-alkoxypropanoate chiral unit containing biphenyl benzoate core laterally substituted by fluorine and bromine have been synthesized and studied. All compounds possess the ferroelectric smectic C* phase over a broad temperature range. For bromine-substituted compounds values of spontaneous polarization reach high values up to 250 nC cm^-2. The effects of the lateral substitution on the phenyl ring far from the chiral centre by methyl and methoxy groups, fluorine, chlorine and bromine atoms on mesomorphic properties and on values of the spontaneous polarization are discussed.     

Some aspects of fluorine chemistry in Göttingen

The review gives a short summary of some developments in fluorine chemistry in Göttingen. A major part covers sulphur-nitrogen-fluorine compounds and their derivatives. Furthermore the chemistry of organometallic fluorides of main group and transition elements is described. Fluorine containing compounds of group 4 and group 13 are good candidates for catalysis and material science.     

Effect of lateral substitution by fluorine and bromine atoms in ferroelectric liquid crystalline materials containing a 2‐alkoxypropanoate unit

Two homologous series of ferroelectric liquid crystalline compounds with 2‐alkoxypropanoate chiral unit containing biphenyl benzoate core laterally substituted by fluorine and bromine have been synthesized and studied. All compounds possess the ferroelectric smectic C* phase over a broad temperature range. For bromine‐substituted compounds values of spontaneous polarization reach high values up to 250 nC cm^?2. The effects of the lateral substitution on the phenyl ring far from the chiral centre by methyl and methoxy groups, fluorine, chlorine and bromine atoms on mesomorphic properties and on values of the spontaneous polarization are discussed.     

某些新的氟代有机硅化合物的合成

本文用含硅氢键化合物与含双键的氟化合物的加成反应,制备了一系列未见报导的含氟有机硅化合物。在用氯丙烯与2,2,3,3-四氟丙醇制2,2,3,3-四氟丙基烯丙醚时,对方法进行了改进,提高了产率。本文还报道了含氟有机硅聚合物方面的工作。     

Study of Fluoroapatite Reactions: The Effect of Metaphosphate Melts on Fluorine-Containing Substances

Abstract

The interaction of metaphosphate melts with fluorine-containing substances was studied. The major variables were composition and temperature. Sodium metaphosphate in contact with fluorides or fluoroapatite gives rise to reactions above 550°C, which liberate fluorine in the form of volatile compounds, mostly as hydrogen fluoride. At least one gas containing phosphorus and fluorine is released from. the melt. Evidence points to phosporyl trifluoride (POF₃). The relative amcunt of HF to POF₃ depends on the concentration of combined hydrogen in the melt and water vapor in the atmosphere above the melt. The rate of the removal of the gaseous reaction products is markedly affected by the depth of the layer through which they have to diffuse. The interaction of metaphosphate melts with fluorides is a general reaction independent of the type of fluoride, and produces the same major products in the gaseous phase. Calcium ions are more effective in furthering the gas evolution from the melt than sodium ions. The structure of synthetic fluoroapatite is destroyed by sodium metaphosphate above 550°C, and under certain conditions the fluorine content of the sample is reduced by 80% within an hour. The yield in the fluorine-containing gases shows a maximum at about 640°C.     

Prototropic processes in benzaurins. <Superscript>19</Superscript>F and <Superscript>1</Superscript>H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols,related fuchsones and benzaurins

Tautomerism of benzaurins and hydration are studied. ¹H and ¹⁹F chemical shifts have been determined for a number of substituted 4-hydroxyphenyl-diphenyl carbinols containing fluorine in a 3-, 3*- or 4*-position, and for similar compounds containing additional methyl groups in a position of 3, 3** or 4**. The same data have been obtained for the fuchsones prepared by dehydration of the above carbinols. On this basis chemical shifts of fluorine in different positions have been evaluated as a monitor of the transformation of 4-hydroxyphenyl group to the semiquinone moiety. The ¹⁹F NMR can be used to monitor the transformation of 4**-fluorobenzaurin and the related 3,3*-disubstituted and 3,3*,5,5*-tetramethylsubstituted compounds to the corresponding carbinols due to the addition of a water molecule and to study the tautomerism of the two latter benzaurins as well as that of 3,3*,4**trifluorobenzaurin. Furthermore, fluorine and methyl group chemical shifts are sensitive to syn-anti-isomerism in substituted fuchsones.     

Determination of oxygen,fluorine and boron by 14-MeV INAA: A case of multiple interferences

Oxygen and fluorine have been simultaneously determined by 14-MeV INAA in samples containing boron. Both boron and fluorine can cause serious interferences in the determination of oxygen. The fluorine and boron interference corrections for oxygen determination have been determined to be 0.43±0.01 and 0.0832±0.0017 apparent g oxygen per g of fluorine and boron, respectively, for our system. Boron can be determined in the same sample by a second irradiation. Mutual interferences have been evaluated and the procedure has been applied to NIST SRM and several other compounds.     

Electrosynthesis of cyclic carbonates from epoxides and atmospheric pressure carbon dioxide

The use of CO(2) for the preparation of value-added compounds has dramatically increased due to increased global warming concerns. We herein report an electrochemical cell containing a copper cathode and a magnesium anode that effectively converts epoxides and carbon dioxide to cyclic carbonates under mild electrochemical conditions at atmospheric pressure.