Synthetic Organic Materials Research Articles

Dissimilarity analysis and automatic identification of monomethylalkanes from gas chromatography mass spectrometry data 1. Principle and protocols

Monomethylalkanes are common but important components in many naturally occurring and synthetic organic materials. Generally, this kind of compounds is routinely analyzed by gas chromatography mass spectrometry (GC–MS) and identified by the retention pattern or similarity matching to the reference mass spectral library. However, these identification approaches rely on the limited standard database or costly standard compounds. When unknown monomethylalkane is absent from the reference library, these approaches might be less useful. In this study, based on the fragmentation rules and empirical observation, many interesting mass spectral characteristics of monomethylalkanes were discovered and employed to infer the number of carbon atoms and methylated position. Combined with the retention pattern, a protocol was described for the identification of monomethylalkane analyzed by GC–MS. After tested by simulated data and GC–MS data of the gasoline sample, it was demonstrated that the developing approach could automatically and correctly identify monomethylalkanes in complicated GC–MS data.

Elemental analysis of organic compounds with the use of automated CHNS analyzers

Results of many years’ worth of studies on the determination of carbon, hydrogen, and nitrogen on automated CHNS analyzers were summarized. Catalytic oxide compositions were selected that allow for the analysis of synthetic and natural organic compounds and materials of any elemental composition and structure: polycyclic, condensed aromatic, heterocyclic, carbonaceous (graphites and carbons), organometallic, organoelement, etc.

Opportunities Abound

Chemistry, both as a basic as well as an applied science, is of fundamental importance to our society. From food to clothing, from construction materials to nanoelectronics, from drugs to dyes, from cars to molecular machines; nothing would be possible without modern chemistry. Although not fully recognized by most people, chemistry is clearly one of the major technologies that have improved drastically the quality of our daily life. Nevertheless, despite the advances made, our science still offers significant challenges for the coming years. I am convinced that chemistry will also play a major role to provide solutions for the crucial problems of the next century: Contributions to the use of alternative energy supplies (hydrogen technology, fuel cells, biomass to liquid, etc.). The introduction of CO2-neutral raw materials for the chemical industry (use of renewable resources, carbon dioxide as a C1 building block, etc.). The development of new pharmaceuticals (against Alzheimer's disease, cancer, HIV) and the enabling of new materials (performance polymers), molecular electronics, and more. And last but not least, more sustainable processes for the production of bulk and fine chemicals (aniline, phenol, caprolactam, propylene oxide, polyurethanes, etc.). What does all of this have to do with ChemSusChem? This new journal, which you are now reading, is devoted in a broad sense to the development of a more sustainable chemistry. Sustainability is the key subject of all the goals mentioned above. ChemSusChem aims to bring together leading chemists from different fields to present their latest accomplishments and delineate the challenges for the future of the important and exiting aspects of sustainability. A glance at the content of the first issue reveals already the broad nature of the field, from improved catalytic methods to applications of renewables, from the conversion of solar energy to research on fuel cells. The interdisciplinary nature of this journal offers interesting opportunities for its readers, and I hope that the scientific content will stimulate chemists from all areas to broaden their horizon and apply their specific knowledge towards sustainability. Whether your interests lie in synthetic organic chemistry, catalysis, energy, environment, materials, renewables, or reaction engineering, we hope that you will enjoy reading ChemSusChem and discover for yourself the emerging state of the art of this exciting field of chemistry. Matthias Beller Rostock, Germany, January 2008

Jumbo squid beaks: Inspiration for design of robust organic composites

The hard tissues found in some invertebrate marine organisms represent intriguing paradigms for robust, lightweight materials. The present study focuses on one such tissue: that comprising the beak of the jumbo squid ( Dosidicus gigas). Its main constituents are chitin fibers (15–20 wt.%) and histidine- and glycine-rich proteins (40–45%). Notably absent are mineral phases, metals and halogens. Despite being fully organic, beak hardness and stiffness are at least twice those of the most competitive synthetic organic materials (notably engineering polymers) and comparable to those of Glycera and Nereis jaws. Furthermore, the combination of hardness and stiffness makes the beaks more resistant to plastic deformation when in contact with blunt abrasives than virtually all metals and polymers. The 3,4-dihydroxy- l-phenylalanine and abundant histidine content in the beak proteins as well as the pigmented hydrolysis-resistant residue are suggestive of aromatic cross-linking. A high cross-linking density between the proteins and chitin may be the single most important determinant of hardness and stiffness in the beak. Beak microstructure is characterized by a lamellar arrangement of the constituents, with a weak interface that promotes crack deflection and endows the structure with high fracture toughness. The susceptibility of this microstructure to cracking along these interfaces from contact stresses at the external surface is mitigated by the presence of a protective coating.

Direct C–H arylation of 3-methoxythiophene catalyzed by Pd. Application to a more efficient synthesis of π-alkoxy-oligothiophene derivatives

The direct regioselective C–H arylation of 3-methoxythiophene and 3,4-ethylenedioxythiophene ( EDOT) was performed successfully under ‘Heck-type’ experimental conditions. This novel synthetic methodology has been used to prepare in a more simple way a series of oligothiophenes interesting for the electronic industry to build new synthetic organic materials.

Alkynyl-substituted phthalocyanines: versatile building blocks for molecular materials synthesis

Phthalocyanines are an interesting class of aromatic macrocycles which possess unique physical and chemical properties that make them excellent building blocks for the construction of molecular materials. Among the different functional groups that can be incorporated into the phthalocyanine's skeleton, the alkynyl group is one of the most interesting; this is confirmed by the large number of organic synthetic materials constructed from acetylene-based scaffolds due its rigidity and linearity, allowing high exciton and electron coupling between chromophore units. Additionally, these systems are particularly important, considering the wide range of functional group interconversions that the triple bond may permit. This account represents a concise overview of the most important contributions on the synthesis and applications of mono- and poly-alkynyl-substituted phthalocyanine-based molecular systems, towards the development of new functional molecular materials.

The ability of biological and organic synthetic materials to accumulate atmospheric particulates containing copper, lead, nickel and strontium

This work was aimed at finding materials that could be used as alternatives to lichens as air quality monitors since the high natural variability and the large amount of lichen collected are two drawbacks of the use of these organisms. Lichen Flavoparmelia caperata(L.) Hale was exposed in three different forms (transplant, detached from the substratum and as a biomass-ground and homogeneized) and compared to the planetree bark (Platanus hybrida Brot.), exposed as a biomass, and two organic synthetic materials (Chelex(R) 100 resin and cellulose acetate). Materials were exposed for two months in the winter, spring and summer, at three Portuguese coastal cities. The results showed that the airborne accumulations of Cu, Ni, Pb and Sr were partially dependent on the meteorological conditions but mainly dependent on the nature of the exposed material. The standard deviations of the synthetic materials or homogenized biomass were the same or greater than lichen transplants or detached. The accumulation by biological materials, of the four studied elements, was comparable to the lichen transplant accumulation. The replacement of the traditional transplants by the biomass was not considered advantageous, since their preparation is time-consuming. Therefore lichens remain the most suitable in biomonitoring studies. The exposure of detached lichen allows the accurate measurement of the exposed area/volume so it can be useful to relate atmospheric deposition rates with the lichen metal content. The synthetic materials accumulated Cu and Ni and should only be used as an alternative to traditional transplants when these are the elements of interest.

Carbon accounting for Japanese petrochemicals

This paper discusses two bottom-up models for the estimation of carbon storage and CO2 emissions related to the nonenergy use of fossil energy carriers. The models show how material flow accounting can be applied to policy making. The nonenergy use emission accounting tables model is a static model, while the chemical industry environmental strategy assessment program (CHEAP) model is a dynamic model of the flows of synthetic organic materials. Both models provide detailed and more accurate estimates of carbon storage in materials than the accounting method that is currently used in the framework of the Intergovernmental Panel on Climatic Change (IPCC) guidelines. The results for both models suggest that carbon storage in synthetic organic materials has been overestimated, and consequently CO2 emissions have been underestimated. Japanese CO2 emissions in 1996 were at least 1.9% higher than reported previously. The CHEAP model results indicate that the net carbon storage (storage − emissions in waste incineration) will decrease during the next few decades. This decrease is mainly driven by changing waste management practice.

Investigation of the effectiveness of absorbent materials in oil spills clean up

The present study examines the absorption capacity of five different types of materials for oil spills clean up. The absorbents were a commercial cellulosic material from processed wood, a commercial synthetic organic fiber from polypropylene and three commercial types of local expanded perlite from the island of Milos. The absorption capacities of the above materials were evaluated in a wet as well as a dry environment with different types of petroleum products. The results showed that commercial types of perlite, in some cases, have absorption capacities comparable to natural and synthetic organic materials used for clean-up applications. The enhancement of the hydrophobic properties of perlite can result in better performance in a water bath. The nature of the spilled oil proved to play an important role in the selection of the proper absorbing material. Overall, the results suggested that partial substitution of commercial synthetic sorbents by mineral materials widely produced in Greece for oil spill clean-up operations is possible, given their friendliness to the environment and their local abundancy.

RESPONSE OF MAIZE (ZEA MAYS) TO TERRALLYT-PLUS (SOIL CONDITIONER) APPLICATION IN CENTRAL ZONE OF NIGERIA

One of the known agricultural practices by which degraded soils can be restored and rehabilitated to an optimum level of productivity is by the use of synthetic organic materials, called soil conditioners. In a greenhouse experiment at the National Cereals Research Institute (NCRI), Badeggi, located in the Southern Guinea Savannah Agro-Ecological Zone (Lat. 9o45'N. Long 6o7'E, Alt. 70.57 metres above sea level) the soil conditioner Terrallyt-Plus was evaluated on soils from three locations within the Central Zone of Nigeria. The results obtained indicate that the addition of Terrallyt-Plus did not improve the yield of maize or the status of the soils.

A Practical Approach to Low Temperature Microscopy and X-Ray Microanalysis

Abstract Water is the most abundant and most important molecule in the hydrosphere, outer lithosphere and the biosphere of our planet. It is also the most abundant and energetically the least expensive building block of living material, forms an integral parts of natural inorganic matrices such as soil and is a constituent of many synthetic organic materials such as paints and polymers. Paradoxically, water does not exist naturally, in the pure state. Water, when converted to the solid state, can provide the perfect matrix in which we may observe the structure and study the in situ chemistry of hydrated samples. We will consider the nature of this solid matrix, and its constituent components in a range of sample, and show how it may be formed, manipulated, examined and analysed. In the short amount of time and space available, one can do little more than highlight the main features of the subject.

Assessment of two different separation techniques for building wastes

It is a well known fact that construction and demolition wastes (C and D wastes) make up 50% of municipal wastes in countries with a high gross domestic product (GDP). Besides questions about the handling of such enormous amounts of waste, problems also occur with the chemical composition of the C and D wastes. The latter problem is the result of the increasing use of synthetic organic materials and heavy metals in construction engineering during the last decades. In this paper two different treatment technologies for C and D wastes are compared, a wet and a dry separation technique. The comparison yielded the following results: both dry and wet technology are not able to select materials according to their chemical composition with the exception of iron, organic carbon and water soluble substances (in the case of wet sorting). Further, it is shown that there are only small differences in the produced fractions of the two plants. Both plants produce a small grain size fraction with the highest content of trace elements, which should be removed prior to reuse. It became obvious that the (chemical) quality of the input is the most important factor in view of the quality of the output fractions. Consequently, this makes separation of C and D wastes at source, a necessity on the way to multiple recycling steps.

Assessment of two different separation techniques for building wastes

It is a well known fact that construction and demolition wastes (C and D wastes) make up 50% of municipal wastes in countries with a high gross domestic product (GDP). Besides questions about the handling of such enormous amounts of waste, problems also occur with the chemical composition of the C and D wastes. The latter problem is the result of the increasing use of synthetic organic materials and heavy metals in construction engineering during the last decades. In this paper two different treatment technologies for C and D wastes are compared, a wet and a dry separation technique. The comparison yielded the following results: both dry and wet technology are not able to select materials according to their chemical composition with the exception of iron, organic carbon and water soluble substances (in the case of wet sorting). Further, it is shown that there are only small differences in the produced fractions of the two plants. Both plants produce a small grain size fraction with the highest content of trace elements, which should be removed prior to reuse. It became obvious that the (chemical) quality of the input is the most important factor in view of the quality of the output fractions. Consequently, this makes separation of C and D wastes at source, a necessity on the way to multiple recycling steps.

Western European Materials as Sources and Sinks of CO2

SummaryMaterials use is an important factor influencing carbon dioxide (CO2) emissions because significant amounts of carbon dioxide are released during the production of materials from natural resources, and because products and wastes can function as important sinks for CO2. This article analyzes the impact of Western European materials use on CO2 emissions. The material flows for steel, cement, petrochemicals, and wood products are analyzed in more detail. The analysis shows that particular characteristics of the materials system must be considered in the development of emission reduction strategies. It is important to select a relatively closed system for policymaking, as in Western Europe, in order to prevent unwanted transboundary effects. The materials stored in the form of products, and the net exports of materials, products, and waste limit the potential of a recycling strategy. Carbon storage in products and waste disposal sites is significant both for synthetic and natural organic materials, but is not accounted for in natural organic materials in current emissions statistics. Accordingly the emissions accounting practices should be modified to reflect the storage of such materials.

Applications of lipase

AbstractLipases are endowed with a substrate specificity that surpasses that of any other known enzyme. This confers on these enzymes an application potential that is literally boundless. Lipases can be employed in the production of pharmaceuticals, cosmetics, leather, detergents, foods, perfumery, medical diagnostics, and other organic synthetic materials. This review attempts to present a comprehensive discussion on the present status of this unique group of enzymes in industry, as well as the actual potential. It represents an endeavor to provide a sincere answer to the question, “What can be done with this enzyme?” as well as, “Can lipase be utilized for this purpose?” It is intended that the manuscript will cover or at least mention all known applications, based on the exploitation of a particular type of reaction catalyzed by lipases. An attempt will be made to cover as large a number of references as possible, so as to further underline the importance and significance of lipase action for industry.

The analysis of synthetic organic materials?A review

Synthetic organic materials consist of polymers, low-molecular-weight additives, and fillers. The review deals with the characterization of the polymer portion in the solid state by inelastic interactions with X-rays and by mass spectrometry (MS). Field desorption MS, secondary ion MS, fast atom bombardment MS, and plasma desorption MS have been used in a molar mass range up to 50000 g/mol. Electrospray or laser desorption MS enable samples of even higher molar mass to be investigated.

Toxic Substances Control in the 1990s: Are We Poisoning Ourselves with Low-level Exposures?

The production of synthetic organic chemicals has risen from less than one billion pounds in 1920 to 23 billion pounds in 1945, 75 billion pounds in 1960, to 213 billion pounds in 1988 (Figure 1) (12, 16). Most Americans wake up to synthetic fabrics in their bed cloths and clothing; they eat food (grown with pesticides and fertilizers made from these synthetic chemicals) packed in plastics; they are transported to their jobs in a vehicle that is composed largely of plastics and fueled by organic chemicals; synthetic materials are an essential part of their work. In addition to the synthetic organic materials, most Americans are exposed to large quantities of natural toxins, such as mercury and lead, and eat numerous natural pesticides and cooking-produced toxic compounds (3, 50). Constant exposure to potentially toxic substances is a fact of modem life-and was a fact of life before the first synthetic chemicals. Toxicology, the science of poisons, is based on the premise stated by Paracelsus in the sixteenth century: All substances are poison; there is none which is not a poison. The right dose differentiates a poison and a remedy (quoted in Ref. 31, p. 16). If, however, the adverse effect is cancer, the prevailing theories hold that there is no safe level of exposure to a genotoxic

What every surgeon should know regarding asbestos-related disease.

Long-lasting occupational exposure to asbestos dust may cause pleural disease, asbestosis, bronchogenic carcinoma and mesothelioma. Many years elapse from first exposure to the appearance of symptoms. Almost all these diseases are the result of dusty working conditions 20-40 years ago. The pathological sequelae are usually irreversible and can progress after exposure ceases. There is no satisfactory treatment. Prevention is the only practical way. In spite of the fact that the general public is invariably exposed to small amounts of the material, asbestos is not a public health problem. Exemptions are the buildings not properly cared for containing sprayed asbestos. But even living in such buildings is calculated to produce a negligible risk of death. Asbestos-related diseases occur where long-lasting inhalation of high amounts of fine asbestos dust has occurred. There is no evidence to indicate that ingested asbestos fibers represent a major health problem. Industry is now replacing asbestos in many products by other fibers. Natural and synthetic organic materials used in fiber cement products are unable to reach the alveoli. They are not cancerogenic and there is no reason to believe that such fibers cause chronic pulmonary disease.

Automated chemical analysis for measuring microgram levels of organic carbon in potable waters

An automated method for the direct determination of microgram levels of organic carbon in potable waters is described. The technique is that of continuous flow analysis and utilizes an automatic sampler, a multiple channel proportioning pump, and an appropriate analytical system (manifold). Samples are acidified, oxygen segmented and passed through a heated inorganic carbon stripper. The stripped liquid is resampled, mixed with silver peroxydisulphate solution and digested at 70°C. The liberated CO 2 is measured by means of infrared photometry. Complete inorganic carbon removal was not possible. From a 30 mg dm −3 inorganic carbon solution 0.1% residual remained after stripping. Using a sample volume of 6.3 cm 3 min −1, full-scale recorder deflection could be obtained for a 1 mg dm −3 organic carbon standard solution with a relative standard deviation of 0.9%. The lower detection limit of practical significance is 50 μg dm −3 organic carbon. The analysis rate is 20 samples per hour. Certain synthetic organic materials resisted complete oxidation and included the amino acids glycine, 1-alanine, leucine, iso-leucine and valine.

An Outdoor Tracking and Erosion Test of Some Epoxide Resins

The resistance of epoxide resins to electrical discharges varies from poor to excellent depending upon the basic resin type and the associated hardener and accelerator. Fillers also have a marked influence on system performance. Epoxides show the greatest promise of the synthetic organic materials available at this time for use under electrical stress outdoors, particularly when the physical properties are considered. The general considerations covering the planning of an outdoor test station and the design of specimens are explained, as well as a general discussion of the results so far obtained at 0.5 and 1.0 kV/in. It has been found that trihydrated alumina is the best antitracking and erosion filler and that plaster of paris causes mechanical failure of the system. Of the resins tested, the cycloaliphatic types, which are now more flexible than when they were originally introduced, are by far the best for outdoor insulators.