Occurrence Of Chlorine Research Articles

Effect of Chlorinated Paraffin Nanoemulsion on the Microstructure and Water Repellency of Ultra-Low Density Fiberboard

This work describes a water repellent ultra-low density fiberboard (ULDF) prepared by chlorinated paraffin nanoemulsion (CPNE). Compared with the untreated ULDF, the contact angle of ULDF treated with 150 mL of CPNE increased from 40° to 134°, while its apparent surface free energy decreased from 24.19 mN/m to 10.06 mN/m. Moreover, the water absorbance of ULDF treated with CPNE decreased from 88.2% to 24% in the first hour. The improved hydrophobicity and hygroscopicity of ULDF was supported by the presence of a film on the surface of fibers, as observed by environmental scanning electron microscopy. The occurrence of chlorine and the chemical structure changes in ULDF before and after CPNE treatment were also confirmed by X-ray photoelectron spectroscopy analysis and Fourier transform infrared spectroscopy respectively. This ULDF with enhanced water repellency is a promising insulation material.

Conclusions

Abstract A crusade is ongoing against element 17 in the periodic table, i.e. chlorine, one of the most abundant on earth. It is blamed, amongst other things, to be responsible for the depletion of the ozone layer, bioaccumulation of chlorinated compounds such as DDT or PCB's in animals and for the formation of dioxins in urban waste incineration. Due to socio-economic implications the issue has gone too early beyond the borders of the scientific community, before facts have been proven and evaluated. As a result, it has been treated in inappropriate and emotional ways even affecting scientific ethics in some cases. Therefore, the International Union of Pureand Applied Chemistry (IUPAC), conscious of its responsibilities in thisarea, has decided to publish this White Book with the collaboration ofoutstanding worldwide renowned scientific specialists from North-America,Europe and Japan in order to inform the public and the decision makersas well as the scientific community in an objective, open and unbiasedway on the up-to-date scientific knowledge. In doing so IUPAC is following its philosophyto make independent judgments on important issues that are touchy or sensitiveto the general public, governments and industry. IUPAC is not acting asa judge, but would like to critically evaluate the various factors forand against a particular issue. The occurrence of chlorine in nature andalso in living organisms, either as inorganic compounds or as numerousand very diversified natural "organo-chlorines" does not makeany doubt any more (T. GRAEDEL and W.C. KEENE, G.W. GRIBBLE). The availability of the raw material, salt,the development of convenient production technologies and the chemicalproperties of chlorine have generated a blooming tree of applicationsin such different fields as the pulp and paper industry (K. SOLOMON),the disinfection of water (H. GALAL-GORCHEV) but mainly in organic synthesisleading to a host of useful products, for example, polymers, pharmaceuticals,pesticides, dyes and pigments (J. FAUVARQUE). It is quite clear that chemists have notalways been aware beforehand of all the possible consequences of havingmanufactured new molecules, be they chlorinated or not. Chemicals emittedvoluntarily or inadvertently in the environment are distributed thereaccording to a complex set of physico-chemical properties (J. MIYAMOTO, K. BALLSCHMITER). Volatile compounds such as aliphatic chlorinatedand chlorofluorinated hydrocarbons find their way to the "atmosphericcompartments". Long-lived members of this family are even able toreach the stratosphere where they have been shown to produce detrimentaleffects to the global environment (M. MOLINA). The substitution of these so-called CFC'sby new shorter-lived molecules has probably been the best example of asound scientific approach to solving environmental problems. A host ofscientific studies has shown that short-lived chlorinated aliphatic compoundsmake only minor or even insignificant contributions to environmental problemssuch as stratospheric ozone depletion, global warming, "photochemicalsmog", "acid rain" or chloride levels in precipitations(J.A. FRANKLIN and H.W. SIDEBOTTOM). Are organo-chlorines harmless or harmful? The question seems as irrelevant as asking if natural compounds areharmless and anthropogenic ones toxic. Ecotoxicity (K. BALLSCHMITER) and toxicity(A. HANBERG) as any other "chemical" property of any compounddepends on the structure of its molecule; chlorinated or otherwise halogenatedcompounds do not escape this rule. Therefore, an undifferentiated banof whole classes of chemical compounds has to be qualified as unscientific. Even in apparently "homogeneous"families such as the dioxins, toxicity varies considerably with the positionand the number of substituents (Ch. RAPPE). There is thus no scientificfoundation to the amalgamation of all chlorinated compounds as a groupshowing special toxic and ecotoxic properties, no more than one shouldconsider organo-oxygens or organo-nitrogens as a whole as harmful becausehighly toxic warfare agents as sarin or tabun contain these atoms in theirmolecules. This obviously doesn't mean that organo-chlorinewaste, as any sort of waste, has not to be managed. The problem has beentackled and technical solutions have been developed to reduce byproductsformation by improving the production processes, to destroy and/or valorisethe remaining production wastes (R. PAPP). This has now to be generalizedin the most economic and environmentally friendly ways. In some cases,post-use recycling is being developed and starts to be generalized asfor the recycling of PVC for which "second life" applicationshave been found (G. MENGES). In conclusion, I would like to add a fewwords formulated by the Nobel laureate Prof. Lord George Porter earlieron. "There is no way that humans can foresee all the consequencesof their actions, .... The only sure foundation for security in this technologicalworld is to have a science base which is continually asking whatever questionsseem interesting and is always there to advise and to act when the needemerges." It is the responsibility of the scientificcommunity to develop this science base, of the media to help them toinform the public in an understandable and unbiased way, of the publicauthority to take the relevant decisions on the bases of sound scienceand not on emotional reactions and of industry to act responsibly, endorsingproduct stewardship and responsible care. This is true for chlorineand its chemistry as well as it is for all human activities.

The occurrence of chlorine in serpentine minerals

Partially serpentinized dunites containing small amounts of Chlorine (< 0.5%) from Dumont, Quebec, and Horoman, Hokkaido, Japan, and one containing less than 0.05% Chlorine from Higashi-Akaishi-Yama, Ehime, Japan have been examined using the electron probe microanalyzer and scanning transmission electron microscope with X-ray analytical capabilities. Chlorine was found together with Si, Mg, Ca and Fe in the serpentine minerals of the Dumont and Hokkaido dunites but not in the Ehime dunite. Chlorine is found associated only with the most finely crystalline facies of the serpentine (grain size less than 10 nm). The Ehime dunite contained no such fine grained serpentine, and was thus effectively chlorine-free, as are the coarser grained serpentines of the other samples. The finegrained chlorine-bearing serpentine also has a much higher concentration of Fe, and can contain smaller amounts of Ca, Ni and Mn than the coarse-grained variety as well as minute awaruite (FeNi3) grains. This fine-grained serpentine probably represents an early stage in the transformation of olivine to serpentine, with chlorine from hydrothermal solutions assisting the necessary chemical changes. The Cl increases the reaction rate by lowering the activation barrier to reaction by the introduction of reaction steps.

Gmelins Handbuch der anorganischen Chemie

IN the volume on chlorine the high standard of excellence reached in the preceding numbers is well maintained, the literature having been exhaustively reviewed up to June 1927. In accordance with the general plan of the work, the volume deals only with the element itself and with such compounds as it forms with the few elements which precede it in the scheme. After a brief account of the history and occurrence of chlorine, its preparation, manufacture, and physical properties are discussed at great length. The attack upon the problem of the separation of the isotopes of chlorine by several different methods is carefully recorded and an instance is quoted of an unusually high value found by Madame Curie for the atomic weight of a sample obtained from an African desert salt. Otherwise the remarkable constancy in the proportions of the isotopes affords evidence of the enormous antiquity of the existing ratio. Then follows an account of the structure of the atom, the dimensions of the molecule, and the various thermal, optical, electrical, and electrochemical properties, and a preliminary survey of the chemical behaviour of the element towards water, non-metals and metals, and a summary of quantitative methods of analysis.

The occurrence of chlorine in coal

The occurrence of chlorine in coal