Organic or organometallic template mediated clay synthesis

A method is given for incorporating diverse varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and LiF for 2 days with an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by US patent No. 3,887,454 issued to Hickson, June 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have water-solubility, positive charge, and thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays

Fossil fuel characterization using laser desorption mass spectrometry: Applications and limitations

Laser desorption mass spectroscopy (LDMS) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI) are applicable to the high molecular weight compounds in fossil fuels which resist intact ionization. LD or MALDI of coals and extracts do not show reproducible ion intensity over mass 2000. This paper describes the scope and limitations of LD and MALD in time-of-flight mass spectrometers applied to high molecular weight molecules such as proteins and polymers. Coal was also analyzed. It is concluded that the sample preparation step is perhaps the most important part in MALDI. Observed high mass ions in coal may be from contaminant proteins. Optimal matrices must be found. Finally, the mass spectrum is senstive to number average molecular weight; a low value, however, does not preclude presence of high molecular weight species

Laser desorption mass spectrometry: Technical limitations, fundamentals, and application to coal

Objective of this study is to assess scope and limitations of laser desorption (LD) and matrix-assisted laser desorption (MALDI) as applied to coals. LD and MALDI mass spectrometry are increasingly used to detect intact molecular species, such as proteins with masses from 1000 to 100,000 amu and beyond. MALDI is also being used for high molecular weight polymers. A good example, related to coal-type systems, is the report on lignin mass spectrometry by MALDI. The mass spectrum shows a wide molecular distribution of several hundred to larger than 16000, with the center of gravity of the distribution around 2600. Results are interpreted in terms of oligomeric lignin molecules. Thus, if there are indeed large molecular species in a polymeric content in coals or coal extracts, MALDI is an attractive technique

Biological sources for phenylalkane hydrocarbons

Linear alkylbenzenes (phenylalkanes) represent an important class of molecular compounds used widely in today`s society as building blocks for detergent manufacture. Evidence is presented to support the proposition in that phenylalkanes in some Australian crude oils and sediments are of geochemical origin rather than resulting from contamination from byproducts of the petrochemical synthesis of surfactants. Evidence presented shows: (1) an unexposed sediment core was found to contain phenylalkanes; (2) the molecular weight range of phenylalkanes in sediments and crude oils is usually wider than that found in surfactants, extending in some cases beyond C{sub 35}; and (3) phenylalkanes were found in the neutral lipid extract of extant {ital Thermoplasma} bacteria. {ital Thermoplasma acidophilum} is an obligate acidiphilic (pH 2) and thermophilic (60{degrees}C), cell wall-less archaeobacterium originally isolated from self-heating coal refuse piles enriched in pyritic materials

Laser desorption mass spectrometry and small angle neutron scattering of heavy fossil materials

The determination of the structural building blocks and the molecular weight range of heavy hydrocarbon materials is of crucial importance in research on their reactivity and for their processing. The chemically and physically heterogenous nature of heavy hydrocarbon materials, such as coals, heavy petroleum fractions, and residues, dictates that their structure and reactivity patterns be complicated. The problem is further complicated by the fact that the molecular structure and molecular weight distribution of these materials is not dependent on a single molecule, but on a complex mixture of molecules which vary among coals and heavy petroleum samples. Laser Desorption mass spectrometry (LDMS) is emerging as a technique for molecular weight determination having found widespread use in biological polymer research, but is still a relatively new technique in the fossil fuel area. Small angle neutron scattering (SANS) provides information on the size and shape of heavy fossil materials. SANS offers the advantages of high penetration power even in thick cells at high temperatures and high contrast for hydrocarbon systems dispersed in deuterated solvents. LDMS coupled with time of flight has the advantages of high sensitivity and transmission and high mass range. We have used LDMS to examine various heavy fossil-derived materials including: long chain hydrocarbons, asphaltenes from petroleum vacuum resids, and coals. This paper describes the application of laser desorption and small angle neutron scattering techniques to the analysis of components in coals, petroleum resids and unsaturated polymers

Small angle neutron scattering applications in fuel science

A wide range of physical and chemical methods have been used to study complex, multicomponent systems in fuel chemistry (crude oil, coal), and we are still far from complete understanding. Since chemical modification and/or solvent extraction of coal result in a number of different systems, it is important to understand the products in terms of their colloidal properties as a function of the solvent type, as well as other physical conditions. This would be helpful in design of processing techniques. Another area of research where SANS can be useful is characterization of the synthetic and modified clays being developed for processing in the petroleum industry. Major limitations for performing SANS experiments are nonavailability/high cost sof certain deuterated solvents and the paucity of beam time at the neutron scattering centers. This paper reports briefly on analysis of coal and asphaltenes

High resolution mass spectrometry for the characterization of complex, fossil organic mixtures

High resolution chemical ionization mass spectrometry data support the notion that the size of the stable aromatic clusters is not large in coals except the very high rank coals and inertinite macerals. The desorption chemical ionization spectra appear representative of the sample with little discrimination for molecular types such as aliphatics

In situ determination of porosity during gasification via saxs/tga

This article discusses the in situ determination of porosity during gasification via saxs/tg

Small-angle neutron scattering evidence for the formation of microporosity in Pittsburgh No 8 Coal following liquefaction pretreatment by solvents

There have been a number of investigations using liquefaction pretreatment which show how liquefaction yields increase following pretreatment. The mechanisms for this are largely unknown but are believed to be connected with increased mass-transfer rates of hydrogen donors which help to limit regressive cross linking reactions. This study only deals with systems that show an increase in liquid products