Thermal analysis and microstructure of solids and solid state reactions

Thermoanalytical and microstructural measurement techniques allow the characterization of solids, their transformation, decomposition, specific surface and pore structure. These techniques are of importance for solids with high specific surface and/or porosity. Thermoanalytical techniques are applied to detect solid state reactions, to determine reaction temperatures and to monitor the progress of the reaction. They are useful to simulate thermal processes in the industry and to receive meaningful results with small samples in a short time. Specific surface, cumulative pore volume and pore volume distribution are obtained by intrusion and absorption techniques. Here selected applications of thermoanalytical and microstructure investigations in modern fields of materials research will be presented, as:

-pore analysis of sintering steps of ceramics,

-secondary structure of catalyst granules,

-template decomposition in zeolites,

-firing process in a composide ceramic tape,

-ignition of coke.

     

Applications of pattern recognition

This poster illustrates the lecture on Pattern Recognition and gives recently published and unpublished examples, mainly from the laboratory from the first author. The applications concern:

- the determination of metabolic pathways of branched chain fatty acids (by clustering),

- the development of a genetic classification of meteorites (by clustering),

- the classification of cholinergic agents according to their interaction with different receptors (by clustering),

- the structure of a data set consisting of gaschromatographic profiles in samples collected in pollution monitoring stations (by factor analysis and pattern recognition),

- factors determining GLC behaviour of solutes (by factor analysis and multiple regression),

- the classification of olive oils according to geographic origin (by principal components and pattern recognition),

- the diagnosis of thyroid status (by pattern recognition).

     

Ein Vektor-Schema für Trennvorgänge

Separation processes, based on different migration speeds of components in mixtures can be reduced to combinations of 3 elements:

1. Migrations, defined by different speeds of components,
2. Shifts, which move all components at the same speed,
3. Gradients, which influence the speed of components in migrations or shifts.

These elements are vectors. They can be used for the better understanding and improvement of existing processes or for planning of new separating methods. Examples for possible new processes are described.     

Limits of cyclodextrin application in oral drug preparations

Cyclodextrins are applied to facilitate formulation problems, to improve stability and bioavailability. Following factors are determining whether or not cyclodextrins can be applied in oral pharmaceutical preparations:

- properties of the selected CD: solubility, price, specific catalytic properties,

- the drug to be complexed: molecular weight, polarity, solubility,

- drug dose

- solubility properties of the complex and the “super solubility” /temporary over-saturation/

- complex stability and possibility to shift the dissociation equilibrium toward the appropriate direction

- legislative procedures

     

Theoretical discussion of methods of elimination of matrix effects in non-dispersive X-ray analysis

Theoretical consideration concerning some possibilities for the elimination of matrix effects in non-dispersive X-ray fluorescence and absorption analysis are discussed. The theoretical treatment is concerned with the following methods:

1. double-channel absorption edge analysis,
2. concentration increase and dilution method in fluorescence analysis,
3. fluorescence-absorption method,
4. emission-transmission method,
5. fluorescence-Compton scattering method,
6. method of multicomponent analysis.

On the basis of the derived formulas, nomographic methods of interpretation of the data are given. Using these methods it is possible to determine unambiguously the concentration of the relevant element. The formulas are also convenient for numerical interpretation. The introduction of the concept of “generalized sensitivity” allows the comparison of various radiometric methods.     

SDS 800 — The new data system for quantitative depth profiling of inhomogeneous samples by SIMS

More than 13 years of SIMS application field experience of numerous users of the ATOMIKA Ionmicroprobes have been the basis for the new SIMS Data System SDS 800. The hardware and software concept of the SDS 800, therefore, pays special attention to the following requirements:

1. Convenient set-up, modification and re-use of the measuring parameter sets for easy, time-saving operation.
2. Individual parameter selection from the very broad range of SIMS measuring parameters for optimum SIMS data quality.
3. Multitasking operation for simultaneous handling of SIMS measurement, data processing, data output and of auxiliary techniques.
4. Simultaneous depth profile/ion image acquisition and processing to enhance data quality and to validate data interpretation.
5. User-friendly data processing and output.

     

Geopolymers and geopolymeric materials

Spectacular technological progress has been made in the last few years through the development of new materials such as ‘geopolymers’, and new techniques, such as ‘sol-gel’. New state-of-the-art materials designed with the help of geopolymerisation reactions are opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry. High temperature techniques are no longer necessary to obtain materials which are ceramiclike in their structures and properties. These materials can polycondense just like organic polymers, at temperatures lower than 100 deg. C. This new generation of materials, whether used pure, with fillers or reinforced, is already finding applications in all fields of industry. Some examples:

pure: for storing toxic chemical or radioactive waste, etc.

filled: for the manufacture of special concretes, molds for molding thermoplastics, etc.

reinforced: for the manufacture of molds, tooling, in aluminum alloy foundries and metallurgy, etc.

These applications are to be found in the automobile and aerospace industries, non-ferrous foundries and metallurgy, civil engineering, plastics industries, etc.     

Charakterisierung der Mischbarkeitseigenschaften binärer Monoschichten durch Messung der Gleichgewichtsspreitungsdrucke

1. The equilibrium spreading pressures were studied as a function of composition of the following binary systems by use of the Wilhelmy-method atT=295 K on aqueous substrate:

octadecyldiethylphosphine oxide/1-hexadecanol (I)

octadecyldiethylphosphine oxide/1-eicosanol (II)

octadecyldiethylphosphine oxide/stearic acid (III)

1. The equilibrium spreading pressures of the pure components of the systems I und II, respectively, decrease due to addition of the corresponding components of mixture. A minimum occurs at the mole fractionx=0,50. The equilibrium spreading pressures of mixtures of system III rise with increasing mole fraction of octadecyldiethylphosphine oxide.
2. The three spreading diagrams are based on one general type. The phase rule is applied and shows that the components of the 3 systems must be immiscible in the monolayer but miscible in the bulk phase.

     

Drug targeting by drug entrapment into ultrafine compartments as carriers

The incorporation of drugs into vesicles is one of several technological methods for the optimization of targeted drug delivery and controlled drug targeting. The main problems will always remain

? To design inert auxiliary accompanying materials in order to overcome side reactions

? To use body-friendly and biodegradable macromolecular carrier materials for the therapeutic system

? To miniaturize the dosage form dramatically in the submicroscopic size range in order to eliminate foreign body irritations

? To develop ultrafine solid and amorphous vesicular compartments (nanocapsules, nanopellets, nanoparticles) to get stable systems with good tissue transfer and organ targeting properties

The actual stand of the incorporation of drugs and biologic active material into ultrafine colloidal solid capsules is reviewed here as for instance:

? Immunoactive material

? Fluorescent indicators in body fluids

? Controlled and sustained release systems

? Nonspecific drug targeting of the first-order (passage through endothelial tissues)

? Second-order targeting (a specific transparenchymal migration), and a highly specific targeting of the third-order (transcellular passage, especially lysosomal transports)

Examples for some of these applications are given. It can be shown that such ultrafine vesiculated capsules offer some advantages when applied parenterally, but also partly for oral application. In the future, still more studies are necessary finally to clarify the importance and practical use of such ultrafine targeting carriers.     

Einsatz der echten Integration in der Atomabsorptions-Spektroskopie

An improvement of the signal-to-noise ratio in atomic absorption spectroscopy may be obtained by each of the following three methods of signal averaging:

increase of the time constant

digital signal averaging

true integration of the signal

The most adequate of these methods appears to be true integration. Two examples are presented to demonstrate the improved signal-to-noise ratio due to the application of this method:

trace analysis of mercury in water by means of flameless AAS. The detection limit appears to be 0.2 ng which corresponds to a concentration of 2 · 10^?13 g/ml.

trace analysis of copper in human urine by means of flame AAS: 1,3 · 10^?8 g/ml copper could be detected without any solvent extraction process.

     

Kompressionsverhalten und Gleichgewichtsspreitungsdrücke binÄrer monomolekularer Dimyristoylkephalin/Dilauroylkephalin-Mischungen

1. The concentration dependence of theF/A-isotherms (premixed spreading, separate spreading) and the equilibrium spreading pressuresF ^e of the system dimyristoyl-cephaline/dilauroyl-cephaline were studied atT=295 K. The results were analysed and compared with respect to the miscibility using thermodynamical criteria.
2. It was shown that various spreading techniques lead to different experimental results. In the case of the premixed spreading it is formed initially an equilibrium monolayer. The analysis of the concentration dependence of the phase transition point (liquid expanded → condensed) shows that the components are completely miscible.
3. From theF/A-isotherms of premixed spreading the A(area)-x ^τ (surface concentrations-diagrams were calculated. The deviation from the ideal behaviour of the A-x ^τ-curves is caused by a phase separation.
4. From the concentration dependence of the equilibrium spreading pressures by means of the surface phase rule follows that the components are approximately ideally miscible.
5. By the analysis of the collapse and equilibrium spreading pressures follows that the mixed films during the compression are in a metastabile state.

     

Parameter distortion by unappropriate nonisothermal treatment

The aim of this contribution is to draw attention to the following problems:

1. boundary conditions of kinetic models,
2. distortion of kinetic data by cutting-off the peak ends,
3. regression analysis involved in the evaluation of kinetic data.

     

Penetration von Polyethylenglycoldodecylethern in gespreitete Methylstearatmonoschichten

1. The penetration isotherms of octaethyleneglycoldodecyl ether and tetraethyleneglycoldodecyl ether in methyl stearate monolayers at different film areas A_M were measured at T=295 K.
2. The penetration isotherms of the system methyl stearate/octaethyleneglycoldodecyl ether depended only weakly on the area of methyl stearate. Also, the relative shift of the penetration isotherms, related to the adsorption isotherm, was small.
3. The general penetration behaviour of both the systems methyl stearate/tetraethyleneglycoldodecyl ether and methyl stearate/octaethyleneglycoldodecyl ether was nearly identical.
4. The thermodynamical analysis of the system methyl stearate/octaethyleneglycoldodecyl ether indicated that the components are only partially miscible.

     

The development of heat flow calorimetry as a tool for process optimization and process safety

Classical thermo-analytical micro methods (DTA, DSC) are still very useful for process work, but medium scale instruments based on heat flow measurement are attaining an increasingly important role in this domain. As in many areas, development of reaction calorimetry for industrial applications was driven by needs and by available means (technical capabilities). The needs have been fairly constant over the past decades. There are data needs:

Reaction rates

Heat release rates

Heat of desired reactions and decompositions

Heat capacities and heat transfer capacities

It took the specialists of calorimetry a long time to recognize and to accept the operational needs, namely:

Working under controlled temperature conditions (constant temperature, temperature ramps)

Adding components during runs (continuously or in portions)

Simulation of industrial mixing conditions

The main driving force for the development of process oriented calorimetric instruments was the evolution of electronic hardware which made the control of heat flow on a (non micro) laboratory scale easy. The paper gives an overview on the principles of heat flow control and reviews the developments of the fifties and sixties, when the matching of heat flow with heat release by reactions was the goal. With the advent of fast and powerful laptop computers, the focus has shifted. Now, the deduction of true heat release rates from signals which may be badly distorted, is the goal. Some recent developments are reviewed and the hope is expressed that calorimetric equipment, inexpensive enough to be affordable for every laboratory engaged in process work, will be available soon.     

Thermal decomposition of algae bloom biomass

The algae bloom biomass in the water reservoir ‘Rybnik’ is an important problem, and not only in Poland [1,2]. The algae growth in the water affects its odour, colour, taste and quality [3]. Algae bloom biomass removed from water can be treated in the following ways:

disposal in sanitary landfills

storage on special dumping grounds

fermentation

dewatering and incineration

In this paper the physicochemical composition and thermal analysis of the biomass of algae bloom dried at 378 K or in the open air are described. Thermal analytical measurements were made in an air atmosphere.     

Phasenumwandlungserscheinungen in Lecithin/Wasser-Systemen

1. By means of differential-scanning-calorimetry the phase transition temperatures and -enthalpies were determined and evaluated for the three following lecithin/water systems: 1,2-dimyristoyl-lecithin/water; 1,2-dipalmitoyl-lecithin/water; 1,2-distearoyllecithin/water.
2. The preparation of the lecithin/water mixtures was made by adsorption of water from the gaseous phase. The adsorption isotherms were evaluated by the BET equation.
3. Four phase transitions were found for the monohydrates of the lecithins. The parameters depend systematically on the length of the alkyl residues.
4. In the heterogeneous two phase region the main-transition and the pre-transition occurred. The thermodynamical parameters of both transitions depend on the alkyl chain length.
5. Whole the results refer to the conclusion that the lecithin head group hydration is a stepwise process. The hydration of the first shell is finished if 5 to 6 molecules water per molecule lecithin are present, while the second hydration shell is complete when about 13 water molecules are adsorbed

     

Enzymatic conversion of cellulosic materials to sugars and alcohol

This techno-economic study deals with the production of sugars and alcohols from cellulosic materials. It covers such key subjects as: potential raw materials; the state-of-the-art on production technologies; the economics of extant processes; and finally infers implications for developing countries from the foregoing. It is clear that a large number of cellulose-, starch-, and sugarcontaining plants can be processed to produce sugars and alcohols. Sugar-containing plants such as sugarcane, sweet sorghum, and nipa palm are the best candidates for the high-yield production of alcohol fuel. Likewise, the starch-containing crops such as cassava, sweet potatoes, yams, taro, and tannia are good candidates, but require an additional step to break down starch to sugar. However, the emphasis of this report is on the major part of biomass containing cellulose and which, therefore, needs special treatment before it can be used to produce glucose and alcohols. To utilize cellulosic containing raw materials the following steps are necessary:

1. Growth, harvest, and delivery of raw materials to processing plants; or, alternatively, the collection and delivery of cellulosic “waste” products.
2. Pretreatment or conversion of the raw material by mechanical, physical, chemical, or enzymatic methods to break down the cellulose to sugars and to modify or remove unwanted side-products, usually lignin and hemicellulose.
3. Recovery and purification of sugars from reaction mixture.
4. Fermentation of sugars to alcohol and purification by distillation.
5. Treatment of process residues to reduce pollution and to recover potentially valuable side-products.

From the considerable research and development work carried out in all areas of pretreatment, it appears acid and enzymatic hydrolysis processes hold the most promise for developing countries. Though acid hydrolysis technology is more advanced, greater ultimate potential is seen in the enzymatic hydrolysis, which is, therefore, recommended for developing countries. The economics of producing alcohol from cellulosic materials is at this time not favorable. Nevertheless, it is recommended that further research and development be undertaken in this area in order to accomplish one or more commercially attractive processes for producing alcohol from fermenting cellulose. If this was accomplished, the developing countries could gain in the following manner:

? Increase self-sufficiency since alcohols can to a great part substitute for petroleum fuels.

? Achieve a better balance of trade.

? Be able to increase employment, especially in rural areas.

? Achieve a higher level of technical competence in biotechnology and related areas.

? Be in a position to expand chemical industries.

? Establish an improved agricultural base by being able to utilize alternative crops and by being able to use what was previously termed agricultural wastes.

     

Non-oral drug preparations containing cyclodextrin complexes

The application of cyclodextrin complexed drugs in non-oral dosage forms results in the following advantages:

- The stability of volatile, chemically unstable drugs is significantly improved by transforming them into cyclodextrin complexes.

- The transformation of oils, liquids into crystalline, solid state provides better physical, mechanical properties, easy to handle products.

- Complex formation/encapsulation on molecular scale/remarkably enhances the dissolution and absorption of lipophylic drugs.

- The formation of water soluble inclusion complexes makes possible the preparation of parenteral dosage forms without using organic solvents or detergents.

     

A family of explicit linear six-step methods with vanished phase-lag and its first derivative

A family of explicit linear sixth algebraic order six-step methods with vanished phase-lag and its first derivative is obtained in this paper. The investigation of the above family of methods contains:

theoretical study of the new family of methods and

computational study of the new family of methods.

The theoretical study of the above mentioned family of methods contains:

1. the development of the method,
2. the computation of the local truncation error,
3. the comparative local truncation error analysis. The comparison is taken place between the new family of methods with the corresponding method with constant coefficients and
4. the stability analysis of the new family of methods. The stability analysis is taken place using test equation with different frequency than the frequency of the test equation used for the phase-lag analysis of the methods.

The application of the new family of linear six-step sixth algebraic order methods to the resonance problem of the one-dimensional time independent Schrödinger equation is used for the computational study of the new family of methods. The result of the above mentioned theoretical and computational investigation is that the new proposed family of linear explicit schemes are computationally and theoretically more effective than other well known methods for the approximate solution of the radial Schrödinger equation and related initial or boundary value problems with periodic and/or oscillating solutions.     

Über die Synthese von substituierten 2-Amino-1-pyrrolinen, 1. Mitt.

Three methods for the synthesis of various substituted 2-amino-1-pyrrolines are described:

1. Cyclization of 2.2-disubstituted 4-bromobutyronitriles with ammonia to yield 3.3-disubstituted 2-amino-1-pyrrolines.
2. Reduction of 2-aminopyrrolin-5-ones or 2-iminosuccinimides with LiAlH₄, a route leading especially to 3.3.4-substituted 2-aminopyrrolines.
3. Chlorination of 4.4-disubstituted pyrrolidones with POCl₃ followed by treatment with NH₃ gives 4.4-disubstituted 2-amino-1-pyrrolines.