19 resultados para ZSM-5 catalyst

em Helda - Digital Repository of University of Helsinki


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Aims. The beginning point of this research was confusion between studies claiming, that children mature Metalinguistic to read at 6-7 of age, and the fact, that in Montessori playschools children easily start writing and reading at age 3 to 5. Aim was also find out how conception of slow Metalinguistic development has started, and if there is some evidence of phoneme awareness of reading of young children in the field of research of reading. Aim was also seek evidence of the sensitive period of reading as Montessori described it. The research also wanted to turn up, if phoneme awareness only develops in children, who work with graphemes and with reading, or could it be found in children, who do not. The mean was to research how the Montessori reading material supports child’s Metalinguistic development, when child begins learning to read. The research plans to represent knowledge about how young children learn to write and read. Methods. Research performed in ordinary kindergarten and in Montessori playschool in Espoo. In kindergarten observed six children, age 3-4, at eight grapheme-rhyme sessions from January to April 2007, and conducting a test based on Chaney’s (1992) study of phoneme awareness of young children. In Montessori kindergarten were observed 17 children about their phoneme awareness and reading competition from January 2007 to March 2008. Their developments in reading were also measured three times from 1.9.07 to 20.3.08 with classification constructed for this study, loosely based on Chall’s (1983) reading stages. The Montessori reading material was analyzed about the influence they have to a child’s Metalinguistic development. This was done based to theory and its concepts from the field of research of reading; phoneme awareness, morphological, syntactical and semantic consciousness. Results and conclusions. Research proved that children 3-5 have naturally developed phoneme awareness. In kindergarten and in Montessori playschool children between 2 and 4 could do phoneme synthesis, and in the latter they also could do phoneme segmentation of words. Montessori reading material guided children gradually, except to read, also to observe and absorb Metalinguistic knowledge. Children learned to write and read. At the last evaluating day almost 50 % of children write and read clauses or stories, and 82 % could read at least words. Children can develop Metalinguistic awareness, while using the Montessori materials for learning to write and read. To reach literacy is easy for children because of their phoneme awareness.

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The literature part of the thesis mainly reviews the results of the use of titanium catalysts for ethene and caprolactone polymerisation. The behaviour of titanium catalysts bearing phenoxy-imino ligands has been the focus of more detailed investigations in ethene polymerisation. Reasons for the production of multimodal polyethene for a range of catalysts are also given. The experimental part of the thesis is divided into two sections based on the monomers used in the polymerisations: Part A (ethene) and part B (caprolactone). Part A: Titanium(IV) complexes bearing phenoxy-imino ligands are known to possess high ethene polymerisation activities after MAO activation. Depending on the ligand, the activities of the catalysts in polymerisation can vary between 1 and 44000 kgPE/(mol*cat*h*bar). Depending on the polymerisation temperature and the electronic and steric properties of the catalyst ligands, low to high molar mass values and uni- and multimodal polydispersity values can been observed. In order to discover the reasons for these differences, 22 titanium(IV) complexes containing differently substituted phenoxy-imino derivatives as di- and tetradentate ligands were synthesised with high yields and used as homogeneous catalysts in ethene polymerisations. Computational methods were used to predict the geometry of the synthesised complexes and their configuration after activation. Based on the results obtained, the geometry of the catalyst together with the ligand substituents seem to play a major role in defining the catalytic activity. Novel titanium(IV) complexes bearing malonate ligands were also synthesised. Malonates are considered to be suitable ligand pre-cursors since they can be produced by the simple reaction of any primary or secondary alcohol with malonylchloride, and thus they are easily modifiable. After treatment with MAO these complexes had polymerisation activities between 10 and 50 kgPE/(mol*cat*h*bar) and surprisingly low polydispersity values when compared with similar types of catalysts bearing the O?O chelate ligand. Part B: One of the synthesis routes in the preparation of the above mentioned phenoxy-imino titanium dichloride complexes involved the use of Ti(NMe2)4 with a range of salicylaldimine type compounds. On reaction, these two compounds formed an intermediate product selectively and quantitatively which was active in the ring-opening polymerisation of caprolactone. Several mono-anionic alcoholates were also combined with Ti(NMe2)4 in different molar ratios and used as catalysts. Full conversion of the monomer was achieved within 15 minutes with catalysts having a co-ordination number of 4 while after 22 hours full conversion was achieved with catalysts having a co-ordination number of 6.

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The commodity plastics that are used in our everyday lives are based on polyolefin resins and they find wide variety of applications in several areas. Most of the production is carried out in catalyzed low pressure processes. As a consequence polymerization of ethene and α-olefins has been one of the focus areas for catalyst research both in industry and academia. Enormous amount of effort have been dedicated to fine tune the processes and to obtain better control of the polymerization and to produce tailored polymer structures The literature review of the thesis concentrates on the use of Group IV metal complexes as catalysts for polymerization of ethene and branched α-olefins. More precisely the review is focused on the use of complexes bearing [O,O] and [O,N] type ligands which have gained considerable interest. Effects of the ligand framework as well as mechanical and fluxional behaviour of the complexes are discussed. The experimental part consists mainly of development of new Group IV metal complexes bearing [O,O] and [O,N] ligands and their use as catalysts precursors in ethene polymerization. Part of the experimental work deals with usage of high-throughput techniques in tailoring properties of new polymer materials which are synthesized using Group IV complexes as catalysts. It is known that the by changing the steric and electronic properties of the ligand framework it is possible to fine tune the catalyst and to gain control over the polymerization reaction. This is why in this thesis the complex structures were designed so that the ligand frameworks could be fairly easily modified. All together 14 complexes were synthesised and used as catalysts in ethene polymerizations. It was found that the ligand framework did have an impact within the studied catalyst families. The activities of the catalysts were affected by the changes in complex structure and also effects on the produced polymers were observed: molecular weights and molecular weight distributions were depended on the used catalyst structure. Some catalysts also produced bi- or multi-modal polymers. During last decade high-throughput techniques developed in pharmaceutical industries have been adopted into polyolefin research in order to speed-up and optimize the catalyst candidates. These methods can now be regarded as established method suitable for both academia and industry alike. These high-throughput techniques were used in tailoring poly(4-methyl-1-pentene) polymers which were synthesized using Group IV metal complexes as catalysts. This work done in this thesis represents the first successful example where the high-throughput synthesis techniques are combined with high-throughput mechanical testing techniques to speed-up the discovery process for new polymer materials.

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This doctoral thesis deals with the syntheses of olefin homo- and copolymers using different kind of metallocene catalyst. Ethene, propene, 1-hexene, 1-hexadecene, vinylcyclohexane and phenylnorbornene were homo- or copolymerized with the catalysts. The unbridged benzyl substituted zirconium dichloride catalysts (1-4), ansa- bridged acenaphtyl substituted zirconium dichloride catalysts, ( 5, 6), rac- and meso-ethylene-bis(1-indenyl)zirconium dichlorides, (rac- and meso-8), rac-ethylene-bis(1-indenyl)hafnium dichloride, ( 12), bis(9-fluorenyl)hafnium dichloride (14 ) enantiomerically pure (R)- phenylethyl[(9-fluorenyl-1-indenyl)]ZrCl2, (11), 14 and asymmetric dimethylsilyl[(3-benzylindenyl-(2-methylbenzen[e]indenyl)] zirconium dichloride, (13), were prepared in our laboratory. Dimethylsilyl-bis(1-indenyl)zirconium dichloride, (9), isopropylidene(9-fluorenyl-cyclopentadienyl)zirconium dichloride, (10), and were obtained commercially. The solid-state structures of the catalysts rac- and meso-1 were determined by X-ray crystallography. Computational methods were used for the structure optimization of the catalyst rac- and meso-1 in order to compare the theoretical calculations with the experimental results. Polymerization experiments were conducted in a highly purified autoclave system using low pressures (< 5 bar) of gaseous monomers. The experiments were designed to attain the optimal catalytic activity and a uniform copolymer composition. The prepared homo- and copolymers were characterized by the gel permeation chromatography, GPC, differential scanning calorimetry, DSC, nuclear magnetic resonance, NMR, and Fourier transform infrared spectrometry, FTIR . Molar mass (Mw, Mn), molar mass distribution (Mw/Mn), tacticity, comonomer content, melting temperature, glass transition temperature, and end group structures and content were determined. A special attention was paid on the correlation of the polymer properties with the catalyst structures and polymerization conditions. An intramolecular phenyl coordination was found in phenyl substituted benzyl zirconocenes 1-3 explaining the decreased activity of the catalysts. Novel copolymers poly(propene-co-phenylnorbornene) and poly(propene co-vinylcyclohexane), were synthesized and high molar mass poly(ethene-co-1-hexene) and poly(ethene-co-1-hexadecene) copolymers with elastic properties were prepared. Activation of a hafnocene catalyst was studied with UV-Vis spectrometry and activation process for the synthesis of ultra high molar mass poly(1-hexene) was found out.

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The use of ionic liquids in chemical research has gained considerable interest and activity in recent years. Due to their unique and varied physicochemical properties, in comparison to molecular solvents, the potential applications for ionic liquids are enormous. The use of microwave irradiation, as a powerful dielectric heating technique, in synthetic organic chemistry has been known since 1986. Since then, it has gained significant recognition for its research and application in both academia and industry. The use of either ionic liquids or microwave irradiation in synthetic organic chemistry has been known to afford improved, alternative or complimentary selectivities, in comparison to traditional processes. In this study, the use of ionic liquids as solvents, co-solvents and catalytic media was explored in Friedel-Crafts, deuterolabelling and O-demethylation reactions. Alternative methods for the production of a variety of aromatic ketones using the Friedel-Crafts acylation methodology were investigated using ionic liquid catalyst or ionic liquid acidic additive systems. The disclosed methods, i.e. metal bistriflamides and chloroindate ionic liquids systems, possessed good catalytic activity in the synthesis of typical benzophenones. These catalytic systems were also recyclable. Microwave irradiation was found to be useful in the synthesis of various polyhydroxydeoxybenzoins and arylpropanones as synthetic precursors to naturally occurring or potentially bioactive compounds. Under optimized condition, the reaction occurred in only four minutes using systems such as [bmim][NTf2]/HNTf2 and [bmim][BF4]/BF3·OEt2. Naturally occurring polyphenols, such as isoflavones, can possess various types of biological or pharmacological activity. In particular, some are noted for their beneficial effects on human health. Isotopically labelled analogues of polyphenols are valuable as analytical standards in the quantification of these compounds from biological matrices. A new strategy for deuterolabelling of polyphenols was developed using ionic liquids as co-solvents and 35% DCl/D2O, as a cheap deuterium source, under microwave irradiation. Under these conditions, perdeuterated compounds were achieved in short reaction times, in high isotopic purity and in excellent yields. An O-demethylation reaction was developed, using an ionic liquid reaction medium with BBr3 for the deprotection of a variety methyl protected polyphenolic compounds, such as isoflavons and lignans. This deprotection procedure was found to be very practical as the reaction occurred under mild reaction conditions and in short reaction times. The isolation and purification steps were particularly straightforward and high yielding, in comparison to traditional methods.

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Environmentally benign and economical methods for the preparation of industrially important hydroxy acids and diacids were developed. The carboxylic acids, used in polyesters, alkyd resins, and polyamides, were obtained by the oxidation of the corresponding alcohols with hydrogen peroxide or air catalyzed by sodium tungstate or supported noble metals. These oxidations were carried out using water as a solvent. The alcohols are also a useful alternative to the conventional reactants, hydroxyaldehydes and cycloalkanes. The oxidation of 2,2-disubstituted propane-1,3-diols with hydrogen peroxide catalyzed by sodium tungstate afforded 2,2-disubstituted 3-hydroxypropanoic acids and 1,1-disubstituted ethane-1,2-diols as products. A computational study of the Baeyer-Villiger rearrangement of the intermediate 2,2-disubstituted 3-hydroxypropanals gave in-depth data of the mechanism of the reaction. Linear primary diols having chain length of at least six carbons were easily oxidized with hydrogen peroxide to linear dicarboxylic acids catalyzed by sodium tungstate. The Pt/C catalyzed air oxidation of 2,2-disubstituted propane-1,3-diols and linear primary diols afforded the highest yield of the corresponding hydroxy acids, while the Pt, Bi/C catalyzed oxidation of the diols afforded the highest yield of the corresponding diacids. The mechanism of the promoted oxidation was best described by the ensemble effect, and by the formation of a complex of the hydroxy and the carboxy groups of the hydroxy acids with bismuth atoms. The Pt, Bi/C catalyzed air oxidation of 2-substituted 2-hydroxymethylpropane-1,3-diols gave 2-substituted malonic acids by the decarboxylation of the corresponding triacids. Activated carbon was the best support and bismuth the most efficient promoter in the air oxidation of 2,2-dialkylpropane-1,3-diols to diacids. In oxidations carried out in organic solvents barium sulfate could be a valuable alternative to activated carbon as a non-flammable support. In the Pt/C catalyzed air oxidation of 2,2-disubstituted propane-1,3-diols to 2,2-disubstituted 3-hydroxypropanoic acids the small size of the 2-substituents enhanced the rate of the oxidation. When the potential of platinum of the catalyst was not controlled, the highest yield of the diacids in the Pt, Bi/C catalyzed air oxidation of 2,2-dialkylpropane-1,3-diols was obtained in the regime of mass transfer. The most favorable pH of the reaction mixture of the promoted oxidation was 10. The reaction temperature of 40°C prevented the decarboxylation of the diacids.

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The purpose of this study is to examine the reception of Matthew 5 in Martin Luther s sermons; in other words to investigate how Luther interprets and applies Jesus teaching of the better righteousness and the law in Mt 5. The study applies the reception-historical approach and contributes to the history of effects and the history of interpretation in New Testament exegesis. The study shows that Luther understands the better righteousness of Mt 5 as good works and fulfillment of the law. Luther s interpretation coheres with the intention of the Evangelist, even if Luther s overall concept of righteousness is foreign to Matthew. In Luther s view righteousness is twofold: The greater righteousness of Mt 5 is the second and the actual righteousness (iustitia activa), which follows the first and the foreign righteousness (iustitia passiva). The first righteousness (faith) is for Luther the work of God, while the second righteousness (good works) is co-operation between a Christian and God. In this co-operation the law, as it is taught by Jesus, is not the opposite of the gospel, but the gospel itself in the sense of Christ as an example . The task of the law is to show the dependence of a Christian on God and to help one to love and to serve one s neighbour (brothers as well as enemies) properly. The study underlines a feature in Luther s thinking that has received little attention in Lutheran theology: Luther insists on preaching the law to Christians. In his view Mt 5 is directed to all Christians and particularly to pastors, for whom Jesus here gives an example of how to preach the law. Luther believes similarly to Matthew that Jesus reveals the real meaning of Mosaic Law and confirms its validity for Christians in Mt 5. Like Matthew, Luther insists on the practicability of the commandments of Mt 5 in his view Christians fulfil the law also with joy yet his interpretation of Mt 5 attenuates the radical nature of its commandments. Luther s reception of the individual pericopes of Mt 5 is considerably generative and occasionally contradictory, which is explained by the following factors, among others: Luther receives many ideas from tradition and reads them and his own theological concepts into Matthew s Gospel. He interprets Mt 5 through his understanding of some Old Testament passages as well as Paul. Most of all, Luther s reception of Mt 5 is shaped by his own experience as a preacher, by his relation to his religious enemies, rulers and to the congregation of Wittenberg. Here Luther shares with Matthew the experience of being opposed and concern about the upright living of the believers, which in both cases also explains the polemical tone of the paraenesis.

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Autuus on katsojan silmässä: lukijakeskeinen tutkimus autuaaksijulistuksista Matt. 5 : 1-12 on reseptioanalyyttisellä metodilla tehty tutkimus siitä, miten akateeminen tutkimuskirjallisuus ja kymmenen valikoitua Jeesus-elokuvaa ovat ymmärtäneet autuaaksijulistusten merkityksen. Kartoitettuaan autuaaksijulistusten tulkintahistoriaa ja Jeesus-elokuvien kulttuurihistoriaa tutkielma kääntyy reseptiohistorialliseksi analyysiksi. Akateemisen tutkimuskirjallisuuden ja Jeesus-elokuvien esittämät tulkinnat Matteuksen evankeliumin autuaaksijulistuksista rinnas-tetaan suhteessa autuaaksijulistusten tyyliin, sisältöön, rakenteeseen ja merkitykseen. Autuaaksijulistusten tyylin tulkinnan analysointi tapahtuu vertailemalla millainen narratiivinen sijainti autuaaksijulistuksille on tarinassa annettu, millaiseksi elokuvat ja tutkimuskirjallisuus tulkitsevat julistusten esitykselliset puitteet sekä mitä näkemyksiä niillä on julistusten kohdeyleisöstä ja Jeesuksen esiintymistavasta. Autuaaksijulistusten sisällön analysointi tarkoittaa yksittäisten autuaaksijulistusten merkityksen selvittelyä. Tämä tapahtuu edelleen Jeesus-elokuvien ja tutkimuskirjallisuuden tekemiä tulkintoja vertailemalla. Näiden lisäksi tekijä esittää oman käännöksensä autuaaksijulistuksista eksegeettisen analyysin keinoin. Käännöksen tavoitteena ei kuitenkaan ole sanatarkkuus, vaan dynaamisuus lukijan tulkinnan säilyttämiseksi. Autuaaksijulistusten rakenteen analysointi esittelee muutamia erilaisia malleja, joiden mukaan tutkimuskirjallisuudessa Matteuksen evankeliumin autuaaksijulistuksia on ryhmitelty. Tässä alaluvussa elokuva-aineiston ja tutkimuskirjallisuuden erot ovat selkeimmin näkyvillä, sillä elokuvat pyrkivät ryhmittelyn sijasta luomaan autuaaksijulistuksille kokonaan uuden rakenteen, joka sopii elokuvakerrontaan julistuslistaa paremmin. Autuaaksijulistusten merkitystä analysoitaessa tutkielmassa asetetaan rinnan kolme Jeesus-elokuvaa, jotka edustavat tulkintahistoriasta tuttuja tulkinnallisia pääsuuntia: autuaaksijulistukset tulkitaan joko eettisiksi kehotuksiksi tai lupauksiksi armosta. Kolmas Jeesus-elokuva edustaa kontroversiaalista näkemystä, joka kiistää molemmat edellä mainitut tulkintatavat. Johtopäätöksissä osoitetaan reseptiohistorialliseen analyysiin viitaten, että tulkintojen muotoutuminen ei ole yksinkertaista. Tulkintaan vaikuttavat paitsi tulkitsijan ennakkokäsitykset, myös tulkittava teksti ja tulkintatilanne. Johtopäätöksissä puolustetaan myös populaarikulttuurin teologisten elementtien tutkimusta osana eksegetiikkaa.

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The work covered in this thesis is focused on the development of technology for bioconversion of glucose into D-erythorbic acid (D-EA) and 5-ketogluconic acid (5-KGA). The task was to show on proof-of-concept level the functionality of the enzymatic conversion or one-step bioconversion of glucose to these acids. The feasibility of both studies to be further developed for production processes was also evaluated. The glucose - D-EA bioconversion study was based on the use of a cloned gene encoding a D-EA forming soluble flavoprotein, D-gluconolactone oxidase (GLO). GLO was purified from Penicillium cyaneo-fulvum and partially sequenced. The peptide sequences obtained were used to isolate a cDNA clone encoding the enzyme. The cloned gene (GenBank accession no. AY576053) is homologous to the other known eukaryotic lactone oxidases and also to some putative prokaryotic lactone oxidases. Analysis of the deduced protein sequence of GLO indicated the presence of a typical secretion signal sequence at the N-terminus of the enzyme. No other targeting/anchoring signals were found, suggesting that GLO is the first known lactone oxidase that is secreted rather than targeted to the membranes of the endoplasmic reticulum or mitochondria. Experimental evidence supports this analysis, as near complete secretion of GLO was observed in two different yeast expression systems. Highest expression levels of GLO were obtained using Pichia pastoris as an expression host. Recombinant GLO was characterised and the suitability of purified GLO for the production of D-EA was studied. Immobilised GLO was found to be rapidly inactivated during D-EA production. The feasibility of in vivo glucose - D-EA conversion using a P. pastoris strain co-expressing the genes of GLO and glucose oxidase (GOD, E.C. 1.1.3.4) of A. niger was demonstrated. The glucose - 5-KGA bioconversion study followed a similar strategy to that used in the D-EA production research. The rationale was based on the use of a cloned gene encoding a membrane-bound pyrroloquinoline quinone (PQQ)-dependent gluconate 5-dehydrogenase (GA 5-DH). GA 5-DH was purified to homogeneity from the only source of this enzyme known in literature, Gluconobacter suboxydans, and partially sequenced. Using the amino acid sequence information, the GA 5-DH gene was cloned from a genomic library of G. suboxydans. The cloned gene was sequenced (GenBank accession no. AJ577472) and found to be an operon of two adjacent genes encoding two subunits of GA 5-DH. It turned out that GA 5-DH is a rather close homologue of a sorbitol dehydrogenase from another G. suboxydans strain. It was also found that GA 5-DH has significant polyol dehydrogenase activity. The G. suboxydans GA 5-DH gene was poorly expressed in E. coli. Under optimised conditions maximum expression levels of GA 5-DH did not exceed the levels found in wild-type G. suboxydans. Attempts to increase expression levels resulted in repression of growth and extensive cell lysis. However, the expression levels were sufficient to demonstrate the possibility of bioconversion of glucose and gluconate into 5-KGA using recombinant strains of E. coli. An uncharacterised homologue of GA 5-DH was identified in Xanthomonas campestris using in silico screening. This enzyme encoded by chromosomal locus NP_636946 was found by a sequencing project of X. campestris and named as a hypothetical glucose dehydrogenase. The gene encoding this uncharacterised enzyme was cloned, expressed in E. coli and found to encode a gluconate/polyol dehydrogenase without glucose dehydrogenase activity. Moreover, the X. campestris GA 5-DH gene was expressed in E. coli at nearly 30 times higher levels than the G. suboxydans GA 5-DH gene. Good expressability of the X. campestris GA-5DH gene makes it a valuable tool not only for 5-KGA production in the tartaric acid (TA) bioprocess, but possibly also for other bioprocesses (e.g. oxidation of sorbitol into L-sorbose). In addition to glucose - 5-KGA bioconversion, a preliminary study of the feasibility of enzymatic conversion of 5-KGA into TA was carried out. Here, the efficacy of the first step of a prospective two-step conversion route including a transketolase and a dehydrogenase was confirmed. It was found that transketolase convert 5-KGA into TA semialdehyde. A candidate for the second step was suggested to be succinic dehydrogenase, but this was not tested. The analysis of the two subprojects indicated that bioconversion of glucose to TA using X. campestris GA 5-DH should be prioritised first and the process development efforts in future should be focused on development of more efficient GA 5-DH production strains by screening a more suitable production host and by protein engineering.