Šezdesetgodišnjica Ziegler-Nattinih katalizatora i stereospecifičnih polimerizacija

This review article highlights the history of the discoveries of organometallic catalysts and stereospecific polymerization of α-olefins, dienes and a number of vinyl monomers by Karl Ziegler and Giulio Natta sixty years ago, their developments and recent progress. As one of the most important achievements in the field of catalysis, macromolecular science and polymer materials, their inventors were awarded the Nobel Prize in Chemistry in 1963 “for their discoveries in the field of chemistry and technology of high polymers”. These discoveries have stimulated an intensive, both basic and applied research all over the world, up to the present times, leading to great development of the polymer industry. The important biographical data and scientific advancements of K. Ziegler and G. Natta are presented as well. Karl Ziegler, a German scientist, Director of Max Planck Institute for Coal Research in Mülheim, besides many scientific achievements, in 1953 discovered a new process for the polymerization of ethylene into linear polyethylene under mild conditions by using titanium chloride and alkyl aluminium catalytic system that was superior to all existing polymerization. Giulio Natta, an Italian scientist, Director of the Department of Industrial Chemistry at Polytechnic, University of Milan, besides many achievements in petrochemical processes, in 1954 obtained for the first time isotactic polypropylene and Montecatini Co. started its production already in 1958. He conducted pioneering studies on the chain microstructure of synthetic organic polymers and postulated the mechanisms of stereospecific polymerizations. Since the discovery of the Zeigler-Natta catalyst, stereospecific polymerization and processes, significant developments have occurred. The breakthrough in polymerization processes such as fluid bed, liquid phase loop reactor and reactor granule technology led to significant development and growth of polyolefin production. In the 1980s, a new family of transition metal complexes known as metallocene catalysts were discovered, based on biscyclopentadienyl and transition metal as Zr, Hf and Ti and appropriate cocatalysts. There major advantage is solubility, high catalytic activity, and the easy tailoring of the polymer microstructure. In 1986, the first synthesis of syndiotactic polystyrene was performed using monocyclopentadienyl/titanium chloride catalyst. The development of catalysts based on diimine complexes of nickel and palladium, and of phenoxy-imino complexes of zirconium and nickel, resulted in polyolefins of different structure and morphology, and many new copolymers of ethylene particularly with polar monomers, producing a variety of new functional polymers, reactive oligomers, and block copolymers. The described discoveries of organometallic catalysts and their applications are one of the most valid models and sources of inspiration for the progress in chemistry and chemical engineering.Prikazana je povijest otkrića, razvitak i mogućnosti organometalnih katalizatora i stereospecifičnih polimerizacija α-olefina, diena i brojnih vinilnih monomera, Karla Zieglera i Giulia Natte, šezdesetih godina 20. stoljeća. Smatraju se najznačajnijim otkrićima u području katalize, makromolekulnih znanosti i polimernih materijala, pa su njihovim autorima 1963. dodijeljene Nobelove nagrade za kemiju. Uz biografske opise i putova njihovih znanstvenih postignuća, opisan je značaj i velik utjecaj tih otkrića na razvitak temeljnih i primijenjenih istraživanja i novih polimerizacijskih postupaka i procesa. Organometalni katalizatori kompleksi su halogenida prijelaznih metala, najčešće titanija, vanadija, kroma, kobalta, nikla i drugih, te metalnih alkila kao što je trietilaluminij, a u većini slučaja nastaju polimeri stereoregularnih struktura. Danas su još uvijek u uporabi poznati kao Ziegler- Nattini (Z-N) katalizatori i Z-N stereospecifične polimerizacije. Karl Ziegler, njemački znanstvenik, direktor Instituta Max Planck za istraživanje ugljena u Mülheimu, uz veliki broj otkrića, godine 1953. razvio je novi postupak polimerizacije etilena u linearni polietilen pri blagim reakcijskim uvjetima uz katalitičke kompleksne spojeve Ti/Al. Giulio Natta, talijanski znanstvenik, direktor Instituta za industrijsku kemiju Sveučilišta u Milanu, istraživao je pretežito katalitičke petrokemijske procese, a 1954. prvi je dobio izotaktni polipropilen polimerizacijom propilena preinačenim Ti/Al-kalizatorom. Postavio je mehanizme stereospecifičnih polimerizacija i utvrdio molekulske strukture organskih polimera. Organometalni katalizatori stalno se usavršavaju pa tijekom 1980-ih dolazi do otkrića i nove skupine tzv. metalocenskih katalizatora na temelju kompleksa supstituiranih diciklopentadiena i prijelaznih metala, posebice Zr, Hf, Sc, Th, Ti. Prednost im je dobra topljivost (homogeni sustavi), velika katalitička aktivnost i stereospecifičnost. Njihovom primjenom 1986. dobiven je i proizvodi se i sindiotaktni polistiren. Otkriveni su također i katalizatori na temelju kompleksa Ni, Pd, Zr i Fe s diiminskim i fenoksiiminskim spojevima kojima se dobivaju poliolefini željene strukture i morfološke građe kao i mnogi funkcijski polimeri, blok-kopolimeri i reaktivni oligomeri. Opisana otkrića i istraživanja organometalnih katalizatora i njihove široke uporabe svrstavaju ih u najbolje primjere razvitka i napretka u kemiji i kemijskom inženjerstvu

Fluorine Magnetic Resonance in Xenon Tetrafluoride

Intrigued by the beautifu,1 result of \u27the Argonne National Laboratory group in synthe ti2iing xenon tetrafluoride1 we thought it worthwhile to look .i nto the nuclear maginetic resonance spectra of this extraordinary -compound, as no such study was announced by the authors

Proton Conductivity in Lithium Sulfate Monohydrate and the Motion of its Water Molecule

Proton conductivity is established in lithium sulfate monohydrate by electrolysis.experiments in the solid state. This effect is discussed in relation to the large amplitude oscillations of the water molecule as evidenced by proton magnetic resonance measurements at different temperatures. The importance of unidirectional chainlike structure of hydrogen bonds in this substance is emphasized, and several implications of the proton conductivity are mentioned

Foreword

SPECIAL SUBJECT ISSUE ON THE STRUCTURE AND PROPERTIES OF POLYMER

Foreword

SPECIAL SUBJECT ISSUE ON THE STRUCTURE AND PROPERTIES OF POLYMER

Proton Magnetic Resonance in Tincalconite

From the 1proton magnetic resonance spectra of tincalconite r ecorded between -1530C and + aooc OH - groups and water molecules were estabHshed. By dehydration at aaoc over P 2 0 5 in vacuum tincalconite loses three water molecules per formula unit with an amoophous rest. The proton resonance line-shape of this dehydration product corresponds to the OH-groups spectrum. The comparison of the experimental curve at low temperature with theoretical ones for two different ratios OH:H20 suggests Na2[B 405(0H)4] · 3H20 as the correct formula for tincalconite. The nature of the motion of the water molecules is discussed

Electrical Conductivity of Borax

The crystal structure of .sodium tetraborate decahydrate (borax) solved in 1956 by Morimoto 1 lead to the actual formula of this compound as B40 5(0H)i · Na2 8 H 2 0. The anionic part of the structure is composed of B,05(0H)4-polyions linked by hydrogen bonds, while the cationic set of the chains is formed by sodium ions surrounded octahedrally with water molecules. These two types of chains are. connected through hydrogen bonds running throughout the crystal parallel to its z-axis

2-Phenyl-4,5,6, 7-tetrahydroindazol-3-one-carboxylic acids. I. Synthesis and Properties

The properties and synthesis of 2-phenyl-4/,5,6,7-tetrahydroindazol- 3-one-5,5-dicarboxylic acid (IID, 2-phenyl-4,5,6,7- tetrahydroindazol- 3-one-5-carboxylic aaid (V) and their ethyl esters II and IV were described. Indazolone dicarboxylic acid III showed the exceptional properties that indicated chelatizing tendencies of this compound. It formed a monohydrate which built in the molecule of crystal water steadily. The content of water was determined by proton magnetic resonance. Potentiometric titrations gave the number of the acidic groups of acids and corresponding esters, as well as the existence of enol form of these compounds. The ultraviolet and infra red absorption spectra were recoDded

Fluorine Magnetic Resonance in Xenon Tetrafluoride

Intrigued by the beautifu,1 result of \u27the Argonne National Laboratory group in synthe ti2iing xenon tetrafluoride1 we thought it worthwhile to look .i nto the nuclear maginetic resonance spectra of this extraordinary -compound, as no such study was announced by the authors

The Postgraduate Study of Macromolecular Sciences at the University of Zagreb (1971-1980)

Postdiplomski studij makromolekularnih znanosti (PSMZ) osnovan je na Sveučilištu u Zagrebu 1971. kao sveučilišni studij u doba kad je sredinom 20. stoljeća došlo do sve snažnijeg interdisciplinarnog prožimanja prirodoslovnih struka - fizike, kemije i biologije te primjene njihovih dostignuća u tehničkim strukama. PSMZ je osnovala skupina istaknutih nastavnika s fakulteta Prirodoslovno-matematičkog, Tehnološkog, Farmaceutsko-biokemijskog i Medicinskog te s Instituta za biologiju. Studij je obuhvaćao glavna područja makromolekularnih znanosti: Organska kemija sintetskih makromolekula, Fizička kemija makromolekula, Strukturna analiza makromolekula, Fizika makromolekula, Biološke makromolekule i Polimerno inženjerstvo s primjenom i preradom polimera, a nastavu 29 kolegija vodilo je 30 nastavnika sa svojim suradnicima. Kad je 1980. promjenom zakonskih propisa u Hrvatskoj prevladalo stanovište da se poslijediplomski studiji moraju vratiti na "matične" fakultete, prestao je postojati i PSMZ. U devet godina postojanja studija magistriralo je 37 stručnjaka za makromolekule. Ocijenjeno je da je PSMZ prije tridesetak godina bio lijep primjer modernog poslijediplomskog usavršavanja i u svjetskim razmjerima. Kako se danas u svijetu uvode slični interdisciplinarni studiji u području makromolekularnih znanosti, to bi ponovno uvođenje nekog suvremenog interdisciplinarnog studija u tom području bilo značajno za daljnji razvoj tih znanosti u Hrvatskoj.The postgraduate study of macromolecular sciences (PSMS) was established at the University of Zagreb in 1971 as a university study in the time of expressed interdisciplinary permeation of natural sciences - physics, chemistry and biology, and application of their achievements in technological disciplines. PSMS was established by a group of prominent university professors from the schools of Science, Chemical Technology, Pharmacy and Medicine, as well as from the Institute of Biology. The study comprised basic fields of macromolecular sciences: organic chemistry of synthetic macromolecules, physical chemistry of macromolecules, physics of macromolecules, biological macromolecules and polymer engineering with polymer application and processing, and teaching was performed in 29 lecture courses lead by 30 professors with their collaborators. PSMS ceased to exist with the change of legislation in Croatia in 1980, when the attitude prevailed to render back postgraduate studies to the university schools. During 9 years of existence of PSMS the MSci grade was awarded to 37 macromolecular experts. It was assessed that the PSMS some thirty years ago was an important example of modern postgraduate education as compared with the international postgraduate development. In concordance with the recent introduction of similar interdisciplinary studies in macromolecular sciences elsewhere in the world, the establishment of a modern interdisciplinary study in the field would be of importance for further development of these sciences in Croatia