The catalytic activation of enones in C-C bond forming processes represents a promising alternative to the prefabrication of chemically labile enols and enolates. Through the use of a (diketonato)cobalt/silane catalyst system, we have devised highly diastereoselective aldol and Michael cycloreductions (J. Am. Chem. Soc. 2001, 123, 5112). Modulation of the catalyst system has enabled the first intramolecular metal-catalyzed alkene (2+2)cycloaddition (J. Am. Chem. Soc. 2001, 123, 6716). Finally, the concept of catalytic nucleophilic enone activation embodied by the Morita-Baylis- Hillman and Rauhut Currier reactions has been utilized to develop an organic catalyst system for the cycloisomerization of bis-enones, i.e. an intramolecular Rauhut Currier reaction (J. Am. Chem. Soc. 2002, 124, 2402). Notably, this protocol allowed for the selective "crossed" cyclization of unsymmetrical bis-enone substrates. / text

No description available.

<p>The ability of amino acids to form nucleophilic enamines with aldehydes and ketones has been used in the development of asymmetric <i>α</i>-oxidation reactions with electrophilic oxidizing agents. Singlet molecular oxygen has for the first time been asymmetrically incorporated into aldehydes and ketones, and the products were isolated as their corresponding diols in good yields and <i>ee</i>’s. Organocatalytic <i>α</i>-oxidations of cyclic ketones with iodosobenzene and <i>N</i>-sulfonyloxaziridine were also possible and furnished after reduction the product diols in generally low yields and in low to good <i>ee</i>’s. Amino acids have also been shown to catalyze the formation of carbohydrates by sequential aldol reactions. For example, proline and hydroxy proline mediate a highly selective trimerisation of <i>α</i>-benzyloxyacetaldehyde into allose, which was obtained in >99 % <i>ee</i>. Non linear effect studies of this reaction revealed the largest permanent nonlinear effect observed in a proline-catalyzed reaction to date. Moreover, polyketides were also assembled in a similar fashion by an amino acid-catalyzed one-pot reaction, and was successful for the trimerisation of propionaldehyde, however the sequential cross aldol reactions suffered from lower selectivities. This problem was overcome by the development of a two-step synthesis that enabled the formation of a range of polyketides with excellent selectivities from a variety of aldehydes. The method furnishes the polyketides via the shortest route reported and in comparable product yields to most multi-step synthesis. All polyketides were isolated as single diastereomers with >99 % <i>ee</i>. Based on the observed amino acid-catalysis, amino acids are thought to have taken part in the prebiotic formation of tetroses and hexoses.</p>

The ability of amino acids to form nucleophilic enamines with aldehydes and ketones has been used in the development of asymmetric α-oxidation reactions with electrophilic oxidizing agents. Singlet molecular oxygen has for the first time been asymmetrically incorporated into aldehydes and ketones, and the products were isolated as their corresponding diols in good yields and ee’s. Organocatalytic α-oxidations of cyclic ketones with iodosobenzene and N-sulfonyloxaziridine were also possible and furnished after reduction the product diols in generally low yields and in low to good ee’s. Amino acids have also been shown to catalyze the formation of carbohydrates by sequential aldol reactions. For example, proline and hydroxy proline mediate a highly selective trimerisation of α-benzyloxyacetaldehyde into allose, which was obtained in &gt;99 % ee. Non linear effect studies of this reaction revealed the largest permanent nonlinear effect observed in a proline-catalyzed reaction to date. Moreover, polyketides were also assembled in a similar fashion by an amino acid-catalyzed one-pot reaction, and was successful for the trimerisation of propionaldehyde, however the sequential cross aldol reactions suffered from lower selectivities. This problem was overcome by the development of a two-step synthesis that enabled the formation of a range of polyketides with excellent selectivities from a variety of aldehydes. The method furnishes the polyketides via the shortest route reported and in comparable product yields to most multi-step synthesis. All polyketides were isolated as single diastereomers with &gt;99 % ee. Based on the observed amino acid-catalysis, amino acids are thought to have taken part in the prebiotic formation of tetroses and hexoses.

The work described in this thesis is divided into four sections: 1. The electrochemical reduction of fluorocarbon derivatives has been investigated. A number of systems have been studied analytically (using cyclic volt amine try) ; whilst preparatively a range of compounds have been synthesised, including semi-conducting polymers and four-membered perfluorocyclic products. 2. The use of sodium amalgam as an electromimetic medium to facilitate reduction of various fluorocarbon substrates has been studied. A series of volatile cyclic and acyclic F-dienes have been prepared from F-alkenes in good yield and conversion. The chemistry of these F-dienes is then described: 3. Both mono- and bi- functional nucleophiles have been reacted, giving a range of novel substitution products. 4. A number of free radical and cycloaddition reactions have been attempted without success. However, the complexation of decamethylferrocene as a metallocene one electron donor, with various F-alkenes of low reduction potential, has allowed a radical anion of a perfluorocyclic-diene to be stabilized and fully characterized for the first time.

Clays are used for long for the control of soil and water pollution as they are inexpensive natural materials with a high adsorption capacity for a wide range of pollutants. However their use as components in engineered waste containment systems is often limited when it comes to the control of organic contaminants as the clays are organophobic in nature. Organic modification of the natural clays, by replacing the exchangeable inorganic cations of clay with organic cations, can facilitate to overcome this limitation. On modification the clays become organophilic which can enhance their sorption capacities for organic contaminants. There are several ways by which natural clays can be modified with organic cations. The type of clay, the type of modifier, and the extent of modification play an important role in enhancing the organic sorption capacity. Sorption of organics by the organo clays depends on a large extent on the specific interactions that occur between modified clay and the organic contaminants. The interaction between the clay and the contaminants depend on the physico-chemical properties of modified clay and nature of organic contaminants. Since the properties of natural clays are likely to be altered by the modification a detailed study has been taken up to understand the physico chemical characteristics of organo clays which essentially control their organic sorption efficiency. Apart from bentonite which is widely used as a component of barrier systems, the characteristics of other types of clays on organic modification also needs to be assessed as they can also form part of the containment system frequently. Further the modification of clays is bound to bring in significant changes on their geotechnical properties which may affect their performance when used as barrier material. Only limited research has been conducted in the past on the geotechnical characteristics of organo clay. Therefore extensive studies have been carried out on the evaluation of the geotechnical characteristics of organo clays and the effect of organic modification on important geotechnical properties. Since very often inorganic and organic contaminants can occur simultaneously, admixtures of bentonite and organically modified clays needs to be employed as a part of clay barrier system. Moreover clay alone is very rarely used as component of barrier systems and significant portion of barrier material usually include non clay fraction. Hence studies have been carried out on mixtures containing different proportions of organo clay and bentonite and sand – organo clay / bentonite to evaluate their geotechnical behavior. Important geotechnical properties considered for detailed studies are swelling, compressibility and permeability. Detailed studies on the organic sorption capacities of different organically modified and unmodified clays, mixtures of bentonite and organo clays have also been conducted. The results of studies conducted are presented in 9 chapters. The organization of the thesis is as follows: Chapter 1 gives detailed background information on the sources and hazards of organic contaminants, inadequacy of conventional barriers to contain organic contaminants, the need for modification of natural clays, and the methods for organic modification of clays. Extensive review of literature has highlighted the need to study the effect of organic modification on the physico chemical and geotechnical properties of clay in different pore fluids. Organo clays were prepared using a wide range of clays viz., two types of bentonites of different regions, black cotton clay and commercially available kaolinite with a long chain organic cation. The extent of organic modification was varied by varying the amount of organic cation exchanged as function of total cation exchange capacity of the clays. Detailed physico chemical characterization of these modified and unmodified clays has been carried out with the help of different state of art techniques. The Chapter 2 brings out the effect of modification, role of type of clay and type of modifiers on the characteristics of organo clays by comparing the physico chemical characteristics of different modified and unmodified clays. The organic modification of montmorillonitc clays with long chain organic cation is found to increase their lattice spacing with the amount of modification whereas no such increase was observed on modification of kaolinitic clays even when all the exchangeable inorganic cations were replaced with the organic cations. The XRD studies revealed that the intercalated organic cations of the modified montmorillonite clays assumed mono, bi, or pseudo tri layer depending on the extent of organic modification. Irrespective of the type of clay modified or the modifier used all the organo clays tend to become e hydrophobic, and the surface area of the clays was found to decrease. A comparison of the characteristics of clays modified in laboratory with organo clay obtained commercially revealed that the organic modification was more effective for the organo clay prepared in the laboratory. As the index properties of all clays are generally correlated with their geotechnical characteristics, the effect of organic modification on the index properties of clays was studied. Chapter 3 presents the effect of organic modification on the plasticity and free swell behavior of clays. The index properties of commercially available organo clay and the unmodified clay used for its preparation were evaluated with pore fluids of different dielectric constants. Fluids of varied dielectric constants were chosen as it is one of the important characteristics to understand the behavior of clays. It was observed that the organic modification of clays reduced the plasticity of the clays in water and increased the plasticity in less polar liquids like ethanol. As the organo clays are more hydrophobic, the water holding capacity and plasticity in water is decreased to a large extent. The free swell behavior of clays in different pore fluids were assessed in terms of the modified free swell index. It was found that trend of variation of free swell index with dielectric constant for modified and unmodified clays, as in the case of plasticity is quite opposite. The swell volume of the modified clays was observed to be controlled more by surface solvation than by the development of the inter particle repulsive forces and diffused double layer. The effect of incorporating unmodified bentonite with organically modified clay on the index properties of bentonite has also been studied. The results suggested that the effect of organo clay addition to bentonite was always to reduce its plasticity and free swell in water. However in pore fluids of lower dielectric an increase in the plasticity and free swell was observed with increasing organo clay content in the mixture. This owes to the fact that organo clays can interact strongly with organic fluids, changing its fabric arrangement. As reported from literature it is well established that the swell of clays has conflicting role on the stability and permeability of clay barriers. Swelling of clays is liable to cause a reduction in hydraulic conductivity, enhance the retention times of contaminants and attribute self healing capacity to the liners. Even though extensive studies have been carried out on the swell behaviour and mechanism of swell of unmodified clays, no systematic research is reported on the effect of organic modification on swell behavior of clays especially in the presence of different pore fluids. Chapter 4 describes the results of oedometer swell tests carried out on compacted samples of modified, unmodified clays and organo clay –bentonite mixture in the presence of different pore fluids such as water, ethanol, and their mixture and carbon tetra chloride. Swelling ability of the unmodified clays was not completely suppressed even in the presence of low polar miscible organic liquids as they were molded at water contents corresponding to the optimum moisture content (OMC). The order of the swelling for the unmodified bentonites was in the order of the polarity of the pore fluids used, while the order is reversed upon organic modification of clays. The mechanism of swell in the case of organo clays in organic liquids was related to the solvation of the organic liquid by the intercalated organic cations. And unlike in the case of unmodified clays, the organo clays showed “solvent induced swelling”. Both organic modification and addition of organo clay to bentonite resulted in the suppression of the swelling of clays in water irrespective of the type of modifier or the extent of organic modification. The Chapter 5 gives a detailed account of the compressibility behavior of organically modified clays and its mixtures with bentonite when the samples were molded with water at their respective OMC and later inundated with different fluids. Significant differences were observed on the compressibility of modified and unmodified clay in different fluids. Organic modification of clays reduced their affinity to water and resulted in lowering the compressibility. However there was an increased compressibility for the organo clays when the samples were inundated with non polar liquids and the compression of the organo clay in non polar fluid was not influenced by the nature of clay nor by the type of modifier. The compressibility of the mixtures of organo clay and bentonite in non polar liquids was generally controlled by the organo clay component of the mixture. Organo clays can be recommended as additives in bentonite slurries for construction of slurry walls in order to improve the containment of organics. But the amendment should not compromise the stability and integrity of the slurry walls. Moreover the influence of addition of sorptive material like organo clay on the compressibility behavior of bentonite slurry has received little attention and needs serious consideration as the studies in the previous chapter has brought out that the compressibility of compacted bentonite reduced significantly on organic modification as well as on addition of orgno clay. The Chapter 6 deals with the compressibility behavior of slurries of unmodified bentonite, organo clay, and their mixtures molded with respective liquid limits with water and later inundated with fluids of different dielectric constants as the slurries frequently get in contact with fluids other than water during their operational life. However it was observed that the effect of polarity of the inundating liquid is masked in all the cases by the presence of large amount of initial molding water as the possible specific chemical interactions between organo clay and non polar fluids were restricted in the presence of large amount of molding water. But the slurry samples molded and inundated with non polar carbon tetra chloride showed that the organo clay samples are more compressible when molded with carbon tetrachloride. The chapter also gives a brief discussion on the effect of initial molding water content on the compressibility of organo clays and its mixtures. The compression was found to increase with increase in initial water content irrespective of the type of inundating fluid in agreement with the behavior observed in the case of unmodified clays. However the effect was less pronounced at higher applied pressures. The Chapter 7 brings out the volume change behavior of organo clay amended sand bentonite mixtures (SOB) which form potential barrier to prevent and /or remove contaminants. The compaction behavior of mixtures showed that the degree of compaction achieved was controlled mainly by the sand content and proportion of organo clay in the total fine fraction. The volume change behavior of the SOB mixtures were assessed with the help of oedometer tests conducted on mixtures compacted at OMC conditions and inundated with different fluids same as those used for the swell tests. The samples with higher sand content showed no observable swell when inundated with liquids viz., water, ethanol and their mixture as all the swollen finer particles were accommodated in the voids created by sand particles. However a high swell percentage was measured when samples with high organo clay content were inundated with carbon tetrachloride. Moreover with increased amounts of organo clay in the mix the swelling of bentonite was suppressed and the same trend continued even when the pore fluids were changed to liquids of medium polarity. The organo clays are capable of interacting strongly with non polar liquids like carbon tetra chloride, and hence an appreciable swell was noted when inundated with them especially in the case of mixtures with high organo clay content. The swell behavior of SOB mixtures with lower sand contents were controlled mostly by the interaction of the pore fluid with bentonite and organo clay, interactions between organo clay and bentonite and the polarity of the pore fluid. As the pore fluid polarity was decreased the influence of organo clay component of the mixture was more pronounced. The Chapter 8 explains the hydraulic performance of modified and unmodified clays along with that of the mixtures of organo clay with bentonite and SOB. The coefficient of permeability was calculated from the consolidation data obtained on sample molded at OMC. The permeability variations observed on changing the pore fluids were studied at each applied pressure. The hydraulic conductivity showed a decreasing trend with the increase in applied pressure for all the clays. The specific interactions of the organo clay with the pore fluids and the clay content were found to play a role in controlling the permeability. Limited tests were carried out to simulate a condition where a SOB liner is proposed as a secondary liner below a punctured geo membrane and its hydraulic performance was evaluated with diesel and water as pore fluids. The permeability coefficients with diesel as permeant were observed to decrease with increase in organo clay content of the mixture irrespective of the applied pressure where as the reverse was true when permeated with water. Thus the use of SOB as secondary liner below storage tanks so as to control the transport of contaminants leaking containments systems is established. The organic sorption efficiency of the modified and unmodified clays and the mixture were evaluated in terms of removal of total organic carbon (TOC) and reduction in chemical oxygen demand (COD) of the different leachates including municipal solid waste (MSW) leachate when treated with different types of modified and unmodified clays. All the modified clays irrespective of the type of clay or the type of modifier used showed improved organic sorption capacity. The sorption of TOC was found to follow a linear sorption mechanism in the case of organo clays and the organic contaminants were partitioned on to the organic phase attached to the organo clays. The composition, age and type of leacahte played a major role in controlling the organic sorption efficiency of organo clays in the case of MSW leachates. The studies done with different mixtures of organo clay and bentonite and SOB mixtures clearly proved that the addition of organo clay always enhanced the organic sorption efficiency of the mixtures. The results are discussed in Chapter 9. The Chapter 10 highlights the major conclusions drawn from the study. The study, apart from satisfying the research zeal on understanding the behavior of organo clays, has generated important information useful for the geo environmental engineer to arrive at appropriate design of barrier systems incorporating organically modified clay, based on the characteristics of pore fluid.

No description available.

Les polyoxométallates suscitent un intérêt de plus en plus grand et ceci dans des domaines d’applications variés. Nous avons synthétisé quatre nouvelles familles organiques de polyoxométallates utilisables en catalyse et en biochimie. Différentes séries d’hybrides covalents ont en effet été isolés et utilisés en tant que catalyseurs dans diverses transformations chimiques. Comme des réactions d’oxydations d’alcools (pour les Organo-POMs sandwich), des réactions d’additions conjuguées (pour les Organo-POMs squaramides), des réductions de quinoléines (pour les Organo-POMs diol-Amides) ou encore des réactions one-Pot d’allylation-Oxydation (pour les Organo-POMs palladium). Par ailleurs, l’étude RMN d’hybrides POMs / peptides a permis de démontrer le repliement des ligands polyglycines autour du POM via liaisons hydrogènes. L’étude par spectrométrie de masse des hybrides POMs / protéines a quant à elle permis de démontrer une interaction sélective et certainement covalente entre un hybride diazirine et le Cytochrome C. / Polyoxometalates attracting interest of more and more and this in various fields of applications. We synthesized four new families of organic polyoxometalates useful in catalysis and biochemistry. Indeed, different covalent hybrid have been isolated and used as catalysts in various chemical transformations. In oxidation reactions of alcohols (for Organo-POMs sandwich), in conjugate addition reactions (for Organo-POMs squaramides), in reductions of quinolines (for Organo-POMs diol-Amide) or in a one-Pot allylation-Oxidation reactions (for Organo- POMs palladium). In addition, NMR studies of hybrid POMs / peptides demonstrated folding of the polyglycines ligand around the POM via hydrogen bonds. The mass spectrometric study of hybrid POMs / protein demonstrated selective and certainly covalent interaction between a diazirin hybrid and Cytochrome C.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Lipases, triacilglicerol Ãster hidrolases E.C. 3.1.1.3, sÃo enziÂmas que atuam nas ligaÃÃes Ãsteres de triacilglicerÃis, liberando Ãcidos orgÃnicos e glicerol. Podendo, em condiÃÃes microaquosas, catalisar a reaÃÃo reversa. Uma limitaÃÃo da utilizaÃÃo destas enzimas em processos industriais reside na falta de estabilidade operacional e na impossibilidade de sua reutilizaÃÃo na forma livre. O uso do sistema de organo-gÃis consiste em uma alternativa para a imobilizaÃÃo de enzimas, e para sua utilizaÃÃo na catÃlise enzimÃtica em meio orgÃnico. Neste sistema a enzima està localizada no centro micelar (centro aquoso) do organo-gel, eliminando o problemas como de estabilizar a enzima contra inativaÃÃo por um solvente nÃo-aquoso. O objetivo deste trabalho foi desenvolver derivados de lipases de Rhizomucor miehei imobilizadas em organo-gÃis à base de polÃmeros, visando à sÃntese de Ãsteres etÃlicos a partir de reaÃÃes de esterificaÃÃo de matÃrias-primas com elevado teor de Ãcidos graxos livres. Os suportes foram obtidos atravÃs de diferentes combinaÃÃes entre os componentes. Utilizaram-se polÃmeros gelatina (Gel), alginato (Alg) ou quitosana (Qui), fases orgÃnicas hexano (Hex) ou heptano (Hep) e os tensoativos dodecilsulfato de sÃdio (SDS) ou brometo de acetilmetilamÃnio (CTABr). Verificou-se a estabilidade tÃrmica da enzima na sua forma livre, determinando seu tempo de meia-vida. Na primeira etapa, foram produzidos derivados com e sem ativaÃÃo via glutaraldeÃdo 2% (v/v). A atividade enzimÃtica foi avaliada atravÃs hidrÃlise do p-nitrofenilbutirato (pNPB). Os derivados foram caracterizados quanto: fator de estabilidade a 60ÂC em relaÃÃo à enzima livre, eficiÃncia e rendimento de imobilizaÃÃo para assim determinar os melhores biocatalisadores. Dentre os catalisadores obtidos, os melhores apresentaram eficiÃncia de 4,1% e fator de estabilidade 30 vezes (Gel/SDS/Hex), eficiÃncia de 6,0% e fator de estabilidade 1,3 vezes (Alg/SDS/Hep) e eficiÃncia de 1,0% e fator de estabilidade de 2,3 vezes (Qui/SDS/Hep). Os suportes produzidos ativados com glutaraldeÃdo 2% (v/v) apresentaram baixas atividades e eficiÃncias, apesar de obterem valores bons de tempo de meia-vida e fator de estabilidade. Os derivados produzidos com o tensoativo CTABr apresentaram baixas atividades, eficiÃncias, tempo de meia-vida e fator de estabilidade. Na segunda fase, os derivados selecionados foram estudados quanto à carga mÃxima (50 U.g-1 a 500 U.g-1) de imobilizaÃÃo e eficiÃncia, nas temperaturas de 15ÂC e 25ÂC. Avaliou-se a aplicaÃÃo dos biocatalisadores na reaÃÃo de esterificaÃÃo do oleato de etila a partir de Ãcido oleico e etanol, variando a razÃo molar Ãcido/Ãlcool e utilizaÃÃo de agente dessecante (zeÃlitas). Verificou-se a estabilidade de estocagem sob 10ÂC por um perÃodo de 100 dias. Todos os derivados apresentaram melhores eficiÃncias utilizando carga de 50 U.g-1, apresentando valores de 4,2% e 4,8% (Gel/SDS/Hex), 2,0% e 2,3% (Alg/SDS/Hep) e 0,9% e 1,1% (Qui/SDS/Hep ) nas temperaturas de 15ÂC e 25ÂC, respectivamente. Nas reaÃÃes de esterificaÃÃo os derivados Gel/SDS/Hex e Alg/SDS/Hep obtiveram maiores conversÃes na razÃo molar Ãcido/Ãlcool 1:10, 72,9% e 16,9%, respectivamente. O derivado Qui/SDS/Hep obteve 80,0% de conversÃo na razÃo de 1:1. Com utilizaÃÃo de zeÃlitas o derivado Gel/SDS/Hex aumentou a conversÃo para 79,0% nas razÃes 1:1 e 1:5, os derivados Alg/SDS/Hep e Qui/SDS/Hep apresentaram decrÃscimo nas conversÃes. Durante os 100 dias de estocagem sob 10ÂC, os derivados Gel/SDS/Hex e Qui/SDS/Hep mantiveram atividade hidrolÃtica atà 40 dias, tendo um decrÃscimo ao longo do tempo. O derivado Alg/SDS/Hep obteve um tempo maior de 60 dias, apresentando tambÃm um decrÃscimo. / Lipases, triacylglycerol ester hydrolases EC 3.1.1.3, are enzymes that act on ester bonds of triacylglycerols, releasing organic acids and glycerol. May in microaquosas conditions, catalyze the reverse reaction. A limitation of using these enzymes in industrial processes is the lack of operational stability and the inability to re-use the free form. The use of organo-gels system is an alternative for the immobilization of enzymes and to their use in enzyme catalysis in organic media. In this system the enzyme is located in the micelle center (aqueous center) of the organo-gel, eliminating problems such as stabilizing the enzyme against inactivation by a non-aqueous solvent. The aim of this work was immobilize lipases from Rhizomucor miehei into organo - gels based on polymers for future application in ethyl esters synthesis through esterification of raw materials with high free fatty acids content. Supports were obtained using different combinations of components. It was used gelatin polymers (Gel), alginate (Alg) and / or chitosan (Chi), organic phases such as hexane (Hex) and heptane (Hep) and surfactants sodium dodecyl sulfate (SDS) or acetylmetylamonium bromide (CTABr). In the first step, derivatives were produced with and without glutaraldehyde 2% (v/v) activation. Enzymatic activity was measured by hydrolysis of p â nitrophenyl butyrate (PNPb). Biocatalysts were characterized as: stability at 60  C and compared to free enzyme, immobilization efficiency and yield factor, thus determining the best biocatalysts. Among the catalysts obtained, (Gel/SDS/Hex) showed the best efficiency of 4.1% , 30 âfold more stable; (Alg/SDS/Hep) with 6.0% efficiency , 1.3 âfold more stable and (Qui/SDS/Hep) with efficiency of 1.0 % , 1.3 âfold more stable than free lipase. Obtained supports activated with glutaraldehyde 2 % (v/v) showed lower activities and efficiencies, in despite of having good values for stability factor. Produced derivatives using surfactant CTABr presented low activity, efficiency and stability factor. In the second step, derivatives were analyzed as maximum load (50 U.g-1 a 500 U.g-1) enzyme immobilization and efficiency at 15  C and 25  C. It was evaluated biocatalysts application in ethyl oleate achievement in an esterification reaction, using oleic acid and ethanol, by varying molar ratio acid / alcohol with and without using of desiccant agent (zeolite) at 37  C and 24 h of reaction. Derivatives were submitted storage stability under 10  C studies, for a period of 100 days. All derivatives showed higher efficiencies using an initial enzyme loading of 50 U.g -1, with values of 4.2% and 4.8% (Gel/SDS/Hex), 2.0 % and 2.3 % (Alg/SDS/ Hep) and 0.9 % to 1.1% (Qui/SDS/Hep) at 15  C and 25  C, respectively. In esterification reactions, Gel/SDS/Hex and Alg/SDS/Hep derivatives showed higher conversions 72.9 % and 16.9 %, respectively, with molar acid / alcohol 1:10. The chemical derivative Qui/SDS/Hep presented 80.0 % conversion with molar acid / alcohol 1:1 ratio. Using zeolites, Gel/SDS/Hex conversion increased to 79.0 % using ratios of 1:1 and 1:5, the Alg/SDS/Hep and Qui/SDS/Hep presented a decreasing in conversions. During 100 days of storage at 10  C, Gel/SDS/Hex and Qui/SDS/Hep hydrolytic activity maintained up to 40 days and a decreasing during this period, however, Alg/SDS/ Hep achieved more than 60 days with activity.

It is over 100 years since scientists first postulated the existence of arynes as reactive intermediates. Their use in organic synthesis is now well-established and investigations into novel methods for their generation and utility in carbon-carbon bond forming reactions continue to this day. In 1983 Kobayashi and co-workers introduced a novel method of generating benzyne under mild conditions, using a fluoride induced decomposition of 2-(trimethylsilyl)phenyl triflate 1. This development has opened the door to employing arynes in a variety of transitionmetal mediated carbon-carbon bond forming processes. Intermolecular carbopalladation, in particular, stands out as a powerful methodology for the construction of diverse 1,2-functionalised arenes through multi-component coupling processes. Initial benzyne carbopalladation with an organopalladium species produces the arylpalladium intermediate 3, which can then undergo a second coupling to any one of the vast numbers of nucleophiles that have been demonstrated to work in palladium cross coupling. Presented herein are investigations towards the realisation of such methodology. Initial efforts focussed on its application to the Heck reaction, using acryates as the nucleophilic component. The chemistry has been developed to incorporate a variety of organo-halides in order to generate a variety of molecular architectures; the resultant 1,2-substituted diaryls being useful in the synthesis of both natural products and medicinal chemistry targets. Following successful development of the Heck reaction, investigations of other palladium catalysed couplings were also undertaken, in particular the Buchwald reaction. Initial mechanistic studies are also discussed.