Kinetic modeling of mechanisms of industrially important organic reactions in gas and liquid phase

This dissertation is based on 5 articles which deal with reaction mechanisms of the following selected industrially important organic reactions: 1. dehydrocyclization of n-butylbenzene to produce naphthalene 2. dehydrocyclization of 1-(p-tolyl)-2-methylbutane (MB) to produce 2,6-dimethylnaphthalene 3. esterification of neopentyl glycol (NPG) with different carboxylic acids to produce monoesters 4. skeletal isomerization of 1-pentene to produce 2-methyl-1-butene and 2-methyl-2-butene The results of initial- and integral-rate experiments of n-butylbenzene dehydrocyclization over selfmade chromia/alumina catalyst were applied when investigating reaction 2. Reaction 2 was performed using commercial chromia/alumina of different acidity, platina on silica and vanadium/calcium/alumina as catalysts. On all catalysts used for the dehydrocyclization, major reactions were fragmentation of MB and 1-(p-tolyl)-2-methylbutenes (MBes), dehydrogenation of MB, double bond transfer, hydrogenation and 1,6-cyclization of MBes. Minor reactions were 1,5-cyclization of MBes and methyl group fragmentation of 1,6- cyclization products. Esterification reactions of NPG were performed using three different carboxylic acids: propionic, isobutyric and 2-ethylhexanoic acid. Commercial heterogeneous gellular (Dowex 50WX2), macroreticular (Amberlyst 15) type resins and homogeneous para-toluene sulfonic acid were used as catalysts. At first NPG reacted with carboxylic acids to form corresponding monoester and water. Then monoester esterified with carboxylic acid to form corresponding diester. In disproportionation reaction two monoester molecules formed NPG and corresponding diester. All these three reactions can attain equilibrium. Concerning esterification, water was removed from the reactor in order to prevent backward reaction. Skeletal isomerization experiments of 1-pentene were performed over HZSM-22 catalyst. Isomerization reactions of three different kind were detected: double bond, cis-trans and skeletal isomerization. Minor side reaction were dimerization and fragmentation. Monomolecular and bimolecular reaction mechanisms for skeletal isomerization explained experimental results almost equally well. Pseudohomogeneous kinetic parameters of reactions 1 and 2 were estimated by usual least squares fitting. Concerning reactions 3 and 4 kinetic parameters were estimated by the leastsquares method, but also the possible cross-correlation and identifiability of parameters were determined using Markov chain Monte Carlo (MCMC) method. Finally using MCMC method, the estimation of model parameters and predictions were performed according to the Bayesian paradigm. According to the fitting results suggested reaction mechanisms explained experimental results rather well. When the possible cross-correlation and identifiability of parameters (Reactions 3 and 4) were determined using MCMC method, the parameters identified well, and no pathological cross-correlation could be seen between any parameter pair.

Catalysis by gold for biomass transformations

The development of new technologies to supplement fossil resources has led to a growing interest in the utilization of alternative routes. Biomass is a rich renewable feedstock for producing fine chemicals, polymers, and a variety of commodities replacing petroleumderived chemicals. Transformation of biomass into diverse valuable chemicals is the key concept of a biorefinery. Catalytic conversion of biomass, which reduces the use of toxic chemicals is one of the important approaches to improve the profitability of biorefineries. Utilization of gold catalysts allows conducting reactions under environmentally-friendly conditions, with a high catalytic activity and selectivity. Gold-catalyzed valorization of several biomass-derived compounds as an alternative approach to the existing technologies was studied in this work. Isomerization of linoleic acid via double bond migration towards biologically active conjugated linoleic acid isomers (CLA) was investigated. The activity and selectivity of various gold catalysts towards cis-9,trans-11-CLA and trans-10,cis-12-CLA were investigated in a semi-batch reactor, showing that the yield of the desired products varied, depending on the catalyst support. The structure sensitivity in the selective oxidation of arabinose was demonstrated using a series of gold catalysts with different Au cluster sizes in a shaker reactor operating in a semibatch mode. The gas-phase selective oxidation of ethanol was studied and the influence of the catalyst support on the catalytic performance was investigated. The selective oxidation of the lignan hydroxymatairesinol (HMR), extracted from the Norway spruce (Picea abies) knots, to the lignan oxomatairesinol (oxoMAT) was extensively investigated. The influence of the reaction conditions and catalyst properties on the yield of oxoMAT was evaluated. In particular, the structure sensitivity of the reaction was demonstrated. The catalyst deactivation and regeneration procedures were studied. The reaction kinetics and mechanism were advanced.

Terpenoid transformations over gold catalysts

Nowadays biomass transformation has a great potential for the synthesis of value-added compounds with a wide range of applications. Terpenoids, extracted from biomass, are inexpensive and renewable raw materials which often have a biological activity and are widely used as important organic platform molecules in the development of new medicines as well as in the synthesis of fine chemicals and intermediates. At the same time, special attention is devoted to the application of gold catalysts to fine chemical synthesis due to their outstanding activity and/or selectivity for transformations of complex organic compounds. Conversion of renewable terpenoids in the presence of gold nanoparticles is one of the new and promising directions in the transformation of biomass to valuable chemicals. In the doctoral thesis, different kinds of natural terpenoids, such as α-pinene, myrtenol and carvone were selected as starting materials. Gold catalysts were utilized for the promising routes of these compounds transformation. Investigation of selective α-pinene isomerization to camphene, which is an important step in an industrial process towards the synthesis of camphor as well as other valuable substrates for the pharmaceutical industry, was performed. A high activity of heterogeneous gold catalysts in the Wagner-Meerwein rearrangement was demonstrated for the first time. Gold on alumina carrier was found to reach the α-pinene isomerization conversion up to 99.9% and the selectivity of 60-80%, thus making this catalyst very promising from an industrial viewpoint. A detailed investigation of kinetic regularities including catalyst deactivation during the reaction was performed. The one-pot terpene alcohol amination, which is a promising approach to the synthesis of valuable complex amines having specific physiological properties, was investigated. The general regularities of the one-pot natural myrtenol amination in the presence of gold catalysts as well as a correlation between catalytic activity, catalyst redox treatment and the support nature were obtained. Catalytic activity and product distribution were shown to be strongly dependent on the support properties, namely acidity and basicity. The gold-zirconia (Au/ZrO2) catalyst pretreated under oxidizing atmosphere was observed to be rather active, resulting in the total conversion of myrtenol and the selectivity to the corresponding amine of about 53%. The reaction kinetics was modelled based on the mechanistic considerations with the catalyst deactivation step incorporated in the mechanism. Carvone hydrogenation over a gold catalyst was studied with the general idea of investigating both the activity of gold catalysts in competitive hydrogenation of different functional groups and developing an approach to the synthesis of valuable carvone derivatives. Gold was found to promote stereo- and chemoselective carvone hydrogenation to dihydrocarvone with a predominant formation of the trans-isomer, which generally is a novel synthetic method for an industrially valuable dihydrocarvone. The solvent effect on the catalytic activity as well as on the ratio between trans- and cis-dihydrocarvone was evaluated.

Explosion-proof requirements for Electrical Machines in Chemical, Oil and Gas Industry in Russia and CIS Countries

One of the main industries which form the basis of Russian Economical structure is oil and gas. This industry is also playing a significant role for CIS countries. Oil and gas industry is developing intensively attracting foreign investments. This situation is providing sustainable development of machinery production for hazardous areas. Operating in oil and gas areas is always related with occurrence of explosion gas atmospheres. Machines for hazardous areas must be furnished with additional protection of different types. Explosion protection is regulated with standards according to which equipment must be manufactured. In Russia and CIS countries explosion-proof equipment must be constructed in compliance with GOST standards. To confirm that equipment is manufactured according to standards’ requirements and is safe and reliable it must undergo the approval procedure. Certification in Russia is governed by Federal Laws and legislation. Each CIS country has its own approval certificates and permissions for operating in hazardous areas.

Targeted Therapy Possibilities for Metastatic Melanoma

The incidence of malignant melanoma of the skin has been steadily rising worldwide during the past decades. Most early detected primary tumors can be removed surgically and the prognosis is good. However, at the same time there still is no permanent cure for metastatic melanoma and its prognosis is poor, although lately new effective drugs have emerged. In this thesis, four different approaches of experimental therapy for metastatic melanoma were studied. Endogenous cis-Urocanic acid (UCA) is found in every individual’s skin, where exposure to UV light from the sun generates it from its inactive trans conformation. Cis- UCA was found to destroy malignant melanoma cells in culture under an acidified pH and sufficient concentration through caspase-3 mediated apoptosis. Furthermore, cis-UCA is able to considerably diminish the growth rate in human melanoma tumors on living SCID mice. Using replication-competent Semliki Forest viruses, human melanoma tumors grown in SCID mice were dramatically shrunken as the fulminant production of viruses in melanoma cells leads them to apoptosis within 72 hours. Small oligopeptides attaching to melanoma cells were identified using in vivo phage display. The melanoma-specific peptides found were further tested in vitro on adenoviruses. Ultimately, the adenoviral retargeting using the peptides was tested in vivo. One peptide homed to human transferring receptor upregulated on melanoma cells. In order to kill the malignant melanoma cells with the retargeted adenoviruses, the viruses should carry genetic material producing apoptotic proteins in the cancer tissue. TIMP-3 has been identified as a good candidate for such a protein, as it inhibits malignant cell adhesion as well as promotes apoptosis through a caspase-8 pathway. It is further shown here that adenovirally delivered TIMP-3 is even more potent, as it could kill non-adherent cancer cells, lacking the fully functional death receptor signalling pathway. Adenovirally delivered TIMP-2 also showed marked antitumor effects in human malignant melanoma xenografts on SCID mice both in ex vivo and systemic delivery.

Integrum - Databases from Russia and CIS - New possibilities for economists

Integrum-aineistokoulutuksen 28.9. - 29.9.2011 materiaali

Integrum - Databases from Russia and CIS - New possibilities for economists

Integrum-aineistokoulutuksen 28.9. - 29.9.2011 koulutusmateriaali

Integrum - Databases from Russia and CIS - New possibilities for political and social studies

Integrum-aineistokoulutuksen 28.9. - 29.9.2011 koulutusmateriaalia

Integrum - Databases from Russia and CIS - New Possibilities for Public Libraries

Integrum-aineistokoulutuksen 28.9. - 29.9.2011 koulutusmateriaalia

A new climatic periodisation of the Gold and Guinea Coasts in West Africa, 1750-1798 : a reconstruction of the climate during the slave trade era, including an analysis of the climatically facilitated Trans-Atlantic slave trade

Avsikten med studien är att producera den första rekonstruktionen av det västafrikanska klimatet mellan 1750 och 1798. Kunskapen om det västafrikanska klimatet före 1800-talet är till dags dato bristfällig, vilket gör det svårare att förstå framtida klimatvariationer. Det är bristen på instrumentell meteorologisk data (temperatur, regnmängd, och lufttryck), vilket i princip bara täcker det senaste århundradet, som är orsaken till att tidigare klimat är bristfälligt kartlagda. Klimatet och miljön är även sådana att proxydata från ’naturens arkiv’ (såsom t.ex. trädringar) har begränsad användning. Således är historiska dokument, främst från gästande kulturer/nationer/intressenter, innehållande deskriptiv information om vädret och klimatet, klimatforskarens viktigaste källa. Genom att använda tidigare, för det här syftet, oanvända källor påvisade den här undersökningen att klimatet i västra Afrika och Guldkusten (Ghana) har ändrats sedan 1700-talet. Monsunregnen var svagare och kortvarigare, speciellt den sekundära regnperioden under hösten var betydligt svagare än idag. Det förekom kraftiga årliga variationer i monsunregnen, men sett ur längre tidsperspektiv utmärktes torrare och blötare perioder. Studien kunde också visa en viss korrelation mellan det globala väderfenomenet El Niño och regnperiodens intensitet längs med kusten. Flera torrperioder sammanföll med tidigare registrerade El Niño sekvenser. Speciellt slutet av 1760-talet påverkades kraftigt av El Niño och även det globala klimatet verkar ha genomgått graftiga förändringar just dessa år. På basis av den nya klimatrekonstruktionen genomfördes också en jämförelse av klimatets inverkan på den transatlantiska slavhandeln från 1750 till 1798, en fråga som historikerna gjort anspelningar på i över 30 år. Utförseln av slavar från västra Afrika var som kraftigast under 1700-talets andra hälft. Analysen visade att slavhandeln delvis tilltog i samband med klimatanomalierna.

α-Pinene oxide and verbenol oxide isomerizations over heterogeneous catalysts

Terpenes are a valuable natural resource for the production of fine chemicals. Turpentine, obtained from biomass and also as a side product of softwood industry, is rich in monoterpenes such as α-pinene and β-pinene, which are widely used as raw materials in the synthesis of flavors, fragrances and pharmaceutical compounds. The rearrangement of their epoxides has been thoroughly studied in recent years, as a method to obtain compounds which are further used in the fine chemical industry. The industrially most desired products of α-pinene oxide isomerization are campholenic aldehyde and trans-carveol. Campholenic aldehyde is an intermediate for the manufacture of sandalwood-like fragrances such as santalol. Trans-carveol is an expensive constituent of the Valencia orange essence oil used in perfume bases and food flavor composition. Furthermore it has been found to exhibit chemoprevention of mammary carcinogenesis. A wide range of iron and ceria supported catalysts were prepared, characterized and tested for α-pinene oxide isomerization in order to selective synthesis of above mentioned products. The highest catalytic activity in the preparation of campholenic aldehyde over iron modified catalysts using toluene as a solvent at 70 °C (total conversion of α-pinene oxide with a selectivity of 66 % to the desired aldehyde) was achieved in the presence of Fe-MCM-41. Furthermore, Fe-MCM-41 catalyst was successfully regenerated without deterioration of catalytic activity and selectivity. The most active catalysts in the synthesis of trans-carveol from α-pinene oxide over iron and ceria modified catalysts in N,N-dimethylacetamide as a solvent at 140 °C (total conversion of α-pinene oxide with selectivity 43 % to trans-carveol) were Fe-Beta-300 and Ce-Si-MCM-41. These catalysts were further tested for an analogous reaction, namely verbenol oxide isomerization. Verbenone is another natural organic compound which can be found in a variety of plants or synthesized by allylic oxidation of α-pinene. An interesting product which is synthesized from verbenone is (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol. It has been discovered that this diol possesses potent anti-Parkinson activity. The most effective way leading to desired diol starts from verbenone and includes three stages: epoxidation of verbenone to verbenone oxide, reduction of verbenone oxide and subsequent isomerization of obtained verbenol oxide, which is analogous to isomerization of α-pinene oxide. In the research focused on the last step of these synthesis, high selectivity (82 %) to desired diol was achieved in the isomerization of verbenol oxide at a conversion level of 96 % in N,N-dimethylacetamide at 140 °C using iron modified zeolite, Fe-Beta-300. This reaction displayed surprisingly high selectivity, which has not been achieved yet. The possibility of the reuse of heterogeneous catalysts without activity loss was demonstrated.