
Dragoslav StoiljkovicUniversity of Novi Sad · Faculty of Technology
Dragoslav Stoiljkovic
PhD
Regular member of Engineering Academy of Serbia
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200
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Introduction
1971-1981 Petrohemija (Panchevo), engineer, start of Factory LDPE
1981-2012 Faculty of Technology (University Novi Sad), professor for synthetic polymers
1982-1988 Adviser for start of HIPOL-Odzaci (PP production) and FIM-Kanjiza (bitumen belts)
1988-1989 Petrochemical complex (Basra, Iraq), adviser for start of LDPE plant
1992-1996 NIS (Novi Sad), collaborator for restructuring of oil, gas, petrochemical and polymer industry of Serbia;
1996-2005 POLY - Consulting for plastics, honorary manager.
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Publications
Publications (200)
A new charge percolation mechanism of olefin polymerization by supported transition metal (Mt) complexes is presented. Mt can exist in different oxidation states and can be easily transformed from one to another state. The partial reduction or oxidation of Mt takes place during the activation: Ti+4 is reduced to Ti(+2); Cr2O3 is oxidized from Cr(+3...
The oxidation state of the transition metal (Mt) active centre is the most disputable question in the polymerization of olefins by Ziegler–Natta (ZN) and metallocene complexes. In this paper the importance and the changes of the Mt active centres are presented and discussed on the basis of a charge percolation mechanism (CPM) of olefin polymerizati...
Despite intensive research over the last 50 years, many questions concerning ethylene polymerization by supported chromium oxide are still unanswered. Hence, the very fundamental issues of this polymerization are discussed in this paper. It is shown that a charge percolation mechanism (CPM) of olefin polymerization by Ziegler–Natta transition metal...
The current explanations of olefin and vinyl monomer polymerization propose that monomer molecules are successively added one by one to the growing polymer chain. This may be true if the monomer molecules exist as individual species in a polymerizing system, e.g. in dilute solutions of monomer. There are cases, however, in which monomer molecules a...
It was proposed in 1955 that ethylene molecules are closely packed and oriented in the course of polymerization at high pressures. Although many papers have been published since that time, there has been no attempt to explain this reaction accounting for the supermolecular organization of compressed ethylene. Recently, we have developed a model tha...
In the 1960ties, Kargin and Kabanov proposed a theory of organized monomer polymerization. In the last four decades, we have successfully applied it to explain the radical polymerizations of compressed ethylene gas and liquid monomers, and olefin polymerization by transition metal complexes. It was found an analogy of high pressure free radical pol...
Нобеловац Ледерман („Божја честица“ 1993) je написао да је Бошковић имао „једну идеју потпуно лудачку за 18. век“ и закључује: „Његова Теорија... је кључ је за целокупну модерну физику“. У овој монографији разматрамо Бошковићеве путоказе који су довели до савремене науке и који омогућавају њен даљи развој, са циљем да укажемо на потребу да се Теори...
The curve, which describes the unique law of forces that exist in nature, was constructed by Boscovich in 1745 on the basis of a philosophical consideration of the collision of two solid bodies, and on the basis of Newton's law of gravitational attraction (1687), Hooke's law according to which the deformation of a body is proportional to the acting...
Бошковић је криву, која описује јединствени закон сила које постоје у природи, конструисао 1745. на основу филозофског разматрања судара два тела и Њутновог закона гравитационог привлачења (1687), Хуковог закона по коме је изобличење тела сразмерно сили која делује на то тело (1675) и Бојл-Мариотовог закона да је производ притиска и запремине конст...
The curve, which describes the unique law of forces that exist in nature, was constructed by Boscovich in 1745 on the basis of a philosophical consideration of the collision of two solid bodies, and on the basis of Newton's law of gravitational attraction (1687), Hooke's law according to which the deformation of a body is proportional to the acting...
The effects of the support to transition metal ratio, the support surface discontinuity, the order of components addition to reactor, the monomer molecules adsorption on the support and their self-organization on the kinetics and polymer structure formation in olefin polymerization by Ziegler-Natta, Phillips and metallocene catalysts are interprete...
Бошковић је криву, која описује јединствени закон сила које постоје у природи, конструисао 1745. на основу филозофског разматрања судара два тела и Њутновог закона гравитационог привлачења (1687), Хуковог закона по коме је изобличење тела сразмерно сили која делује на то тело (1675) и Бојл-Мариотовог закона да је производ притиска и запремине конст...
На основу обједињене теорије Руђера Бошковића и теорије Павла Савића и Радивоја Кашанина утврдили смо да у флуидима постоје три граничне линије за фазне прелазе вишег реда на изохорама 2Vc, Vc (Видомова линија) и Vc/2 (Френкелова линија), где је Vc критична запремина. Сходно томе, постоји неколико фаза, а свака се састоји од две врсте молекулских и...
Based on the unified theory of Ruđer Bošković and the theory of Pavle Savić and Radivoj Kašanin, we determined that in fluids there are three boundary lines for higher-order phase transitions on the isochores 2Vc, Vc (Widom's line) and Vc/2 (Frenkel's line), where Vc critical volume. Accordingly, there are several phases, each consisting of two typ...
Од теорије Руђера Бошковића (1711 - 1787.) до теорије Павла Савића (1909 - 1994.) и Радивоја Кашанина (1892 - 1989.) је раздобље од два века. Прва теорија се темељи на закону континуитета и полази од начела класичне Њутнове механике, а друга се заснива на квантној механици. Уз то, Бошковић је свој закон сила примењивао углавном на примарне елементе...
From the theory of Roger Boscovich (1711-1787) to the theory of Pavle Savich (1909-1994) and Radivoj Kashanin (1892-1989) is a period of two centuries. The first theory is based on the law of continuity and starts from the principles of classical Newtonian mechanics, and the second is based on quantum mechanics. In addition, Boscovich applied his l...
From April 5th , 1757 to March4 th , 1758, Roger Boscovich stayed in Vienna, where he was an expert and leader on behalf of the Republic of Luka in its dispute with the Duchy of Tuscany, which built dams on the border river which caused floods in the fields of Lucca. During that stay, Boscovich wrote his monumental work "Theory of Natural Philosoph...
Despite the extensive studies, the exact role of methyl aluminoxane (MAO) in olefin polymerization by transition metal active centers is still an open question, particularly, why a large excess of MAO is required. The optimal molar ratio of MAO and metallocene (Mt) precursor is 5000 to 10000!? This empirical fact cannot be explained by the generall...
(Šesto predavanje - Ciklus PUTOKAZIMA RUĐERA BOŠKOVIĆA KA BUDUĆNOSTI PRIRODNIH NAUKA)
Od Boškovića posredstvom Maksvela do Tesle. Uticaj Boškovićeve Teorije na savremenike i sledbenike. Ocena Leona Ledermena i vaskrsnuće Boškoviće Teorije. Video snimak predavanja je na YouTube https://www.youtube.com/watch?v=VPgFssxeQvQ
(Peto predavanje - Ciklus PUTOKAZIMA RUĐERA BOŠKOVIĆA KA BUDUĆNOSTI PRIRODNIH NAUKA)
Atrakcija (A) i repulzija (R) su: Ljubav i mržnja (Empedoklo); privlačna i odbojna sila (Njutn, Bošković, Kant); sastavljanje i rastavljanje (Hegel) i kretanje, tj. približavanje i udaljavanje (Engels). Zbir svih atrakcija jednak je zbiru svih repulzija, Zbir A =...
Karakteristične zapremine materije - smisao i izračunavanje; Nadmolekulska organizacija i fazno stanje gasova i tečnosti; Struktura vode. Teorija polimerizacije organizovanih molekula. Video snimak predavanja je na YouTube https://www.youtube.com/watch?v=cM9cXE3kJb4&t=7s
Tesla o Boškoviću i relativnosti; Bošković o prostoru i vremenu kako ih mi spoznajemo; Boškovićevo shvatanje relativnosti kretanja; Kretanje dva tela na paralelnim i unakrsnim putanjama; Neka otvorena pitanja: tačnost merenja Hablove konstante, definicija 1. i 2. Njutnovog zakona u slučaju relativnog kretanja dva tela. Video predavanja je na YouTub...
Ruđer Bošković je 1758. objavio “Teorija prirodne filozofije svedena na jedan jedini zakon sila koje postoje u prirodi”. Pavle Savić i Radivoj Kašanin su 1960-tih objavili teoriju o ponašanju materije pri visokim pritiscima i o nastanku rotacije nebeskih tela. U predavanju se ukazuje na povezanost Boškovićevе teorije i teorije Savića i Kašanina i n...
Uobičajeni prikaz istorije otkrića strukture atoma, molekula i makromolekula; Doprinos Boškovićeve Teorije otkriću strukture atoma; Boškovićevo shvatanje elementarnih tačaka, atoma i molekula; Makromolekulska hipoteza Boškovića; Boškovićevi putokazi ka neutrinu, gluonima, kvarkovima, nano-cevčicama, dijamantu, grafitu; Potvrde Boškovićevog zakona s...
Život i delatnost Ruđera Boškovića; „Teorija prirodne filozofije svedena na jedan jedini zakon sila koje postoje u prirodi“; Orbitale u Boškovićevoj Teoriji; Kvantni smisao Boškovićeve Teorije. Snimak predavanja je na Yu Tube https://www.youtube.com/watch?v=NlLU0FeXdUk&t=81s .
Despite seven decades of intense research, the generally accepted insertion mechanism (IM) has generated many open questions. It is shown in this paper why IM is incorrect and nonsense. We reexamined the fundamental presumption of this polymerization, evaluated the roles of each basic component and proposed an alternative mechanism by electric char...
Note: The Part 3 is in Serbian language. The similar article, which includes all parts, has been published in English: https://www.researchgate.net/publication/340334769_TANGO_OF_MOLECULES_-_OUR_WAY_TO_DISCOVER_THE_SUPRAMOLECULAR_STRUCTURE_OF_GASES_AND_LIQUIDS
In our previous works, from 1978 to 2019, we described the supramolecular structure and...
In liquid and gaseous water, as in other substances, there are three boundary lines for higher-order phase transitions on the isochores 2Vc, Vc and Vc /2, where Vc is critical volume. Accordingly, there are several phases, and each consists of two types of molecular and/or supramolecular particles in mutual equilibrium: translating ⇄ 3D rotating in...
Pored dobro poznatih graničnih linija za fazne prelaze 1. reda u fluidima, tj. topljenje⇄očvršćavanje i ključanje⇄kondenzacija, postoje tri granične linije na izohorama 2Vc, Vc i Vc/2 za fazne prelaze višeg reda. Čvorne tačke za sve ove granične linije leže na liniji koegzistencije tečnost-para. Shodno tome, postoji nekoliko faza u fluidima, a svak...
The well-known triple point and critical point, located on the liquid-vapor coexistence (LCV) curve, represent the nodal points for the beginning of the melting (or liquid solidification) line and the so-called Widom line, respectively. In this paper, it was shown that there are two additional nodal points, where the isochores Vr=0.5 and Vr=2 join...
Note: The 2nd Part is in Serbian language. The similar article, which includes all parts, has been published in English: https://www.researchgate.net/publication/340334769_TANGO_OF_MOLECULES_-_OUR_WAY_TO_DISCOVER_THE_SUPRAMOLECULAR_STRUCTURE_OF_GASES_AND_LIQUIDS
In our previous works, from 1978 to 2019, we described the supramolecular structure a...
In 1983 and 1995, we published papers in which we derived a very simple mathematical model which represents the relationships between the molar volumes of characteristic points of matter. It was recognized that two characteristic points are well-known points on the liquid-vapor Pr-Vr coexistence curve, i.e. critical point and triple point. The ques...
Nedavno je grupa naučnika iz Amerike postigla napredak u spoznaji strukture tečnosti i komprimovanih gasova. Pokazalo se da su njihovi rezultati u saglasnosti sa našim, do kojih smo došli još pre četrdesetak godina.
(Recently, a group of scientists from America made progress in understanding the structure of liquids and compressed gases. It turned...
„Eristička dijalektika ili umeće kako da se uvek bude u pravu objašnjeno u 38 trikova“ je nedovršen rukopis nađen u zaostavštini nemačkog filozofa Artura Šopenhauera (1788−1860). Pod „erističkom dijalektikom“ on podrazumeva vođenje rasprave (spora, polemike), tako da se, svesno ili nesvesno, služeći nekim tipičnim trikovima, osigura prednost i uvek...
Од теорије Руђера Бошковића (18. в.) до теорије Павла Савића и Радивоја Кашанина (20. в.) је раздобље од два века. Прва теорија се темељи на закону континуитета и полази од начела класичне Њутновое механике, а друга се заснива на квантној механици. Уз то, Бошковић је свој закон сила примењивао углавном на примарне елементе материје (непротежне и не...
"Eristic dialectics or the Art of Being Right: 38 Ways to Win an Argument" is an unfinished manuscript found in the legacy of the German philosopher Arthur Schopenhauer (1788-1860). In the previous articles and this final one, we presented some tricks that he described, but also some others. We describe them by the examples from the world of polyme...
Three decades ago we proposed Charge Percolation Mechanism (CPM) of olefin polymerization by Ziegler-Natta, Phillips, and metallocene catalysts. We developed the computer program "Lattice" to simulate polymerization by CPM and verified the simulations by the results of real experiments published in the literature. These simulations have been publis...
Both chromium oxide and several metallocenes, which are used in the manufacture of polyethylene, were deposited onto a variety of solid oxides, under a variety of conditions, and the resulting support effects were observed and compared in [1]. Although using seemingly different chemistries, the two catalyst systems exhibited a surprising number of...
ABSTRACT: "Eristic dialectics or the Art of Being Right: 38 Ways to Win an Argument" /1/ is an unfinished manuscript found in the legacy of the German philosopher Arthur Schopenhauer (Arthur Schopenhauer, 1788-1860). In the previous, this and in the following parts, we present some tricks that he described, but also some others. We describe them by...
Unlike most other olefin polymerization catalysts, the Cr/SiO2 Phillips catalyst does not require any activator to develop its activity, as it is activated by the addition of a monomer to be polymerized. However, it is known that the addition of a small amount of metal-alkyls has drastic effects on the catalyst performance. In cited work [1], autho...
ABSTRACT: "Eristic dialectics or the Art of Being Right: 38 Ways to Win an Argument" is an unfinished manuscript found in the legacy of the German philosopher Arthur Schopenhauer (1788-1860). In this and in the following articles, we present some tricks that he described, but also some others. We describe them by the examples from the world of poly...
Suprotno predviđanjima klasične teorije, radikalnu polimerizaciju mnogih monomera u masi ili koncentrovanim rastvorima karakteriše pojava samoubrzanja nakon dostizanja određenog stepena reagovanja. Prva saznanja i tumačenja ovog fenomena javljaju se krajem tridesetih i početkom četrdesetih godina 20. v. Od tada pa do danas samoubrzanje radikalne po...
The order of the components addition in olefin polymerization by metallocene/MAO systems has the great effects on polymer yield, molecular mass and molecular mass distribution. The theoretical consideration based on the charge percolation mechanism (CPM) predicts that SMA order of addition (i.e. MAO + Monomer +Metallocene precursor) contributes to...
It was published in the mentioned article that two FI Zr-types of metallocenes were used as catalyst precursors for ethylene polymerization at different methyl aluminoxane (MAO) to Zr ratios: [MAO]/[Zr]= from 25000 to 125000. In these comments, the effects of the type of Zr precursors and the ratio of [MAO]/[Zr] on catalyst activity, molecular mass...
The empirical fact that the extremely large excess methyl aluminoxane (MAO) is required for olefin polymerization by the metallocenes is almost the four-decades mystery, which cannot be explained by the current theory of Ziegler-Natta polymerization based on the Arlman-Cossee insertion mechanism (IM). As an alternative to IM, we implemented the cha...
Based on Boscovich's understanding of the relativity of motion, mathematical expressions for the relative motion of two bodies on parallel and cross paths are derived. Some current issues of modern science are briefly discussed, e.g. Hubble's law, the theory of relativity, but also Newton's laws. It is not our intention to challenge and support the...
На основу Бошковићевих схватања о релативности кретања изведени су математички изрази за релативно кретање два тела на паралелним и унакрсним путањама. Укратко су разматрана нека актуелна питања савремене науке, нпр. Хаблов закон, теорија релативности, али и Њутнови закони. Није нам намера да оспоравамо ии подржавамо схватања савремене науке, већ с...
According to Kargin and Kabanov the polymerization of monomers in a higher degree of orderliness is characterized by the phenomena: induction period, self-acceleration of the reaction, low energy of activation, and the absence of a chain termination reaction.
In this article, it is shown that all these phenomena are detected in the radical polymeri...
The phase transitions and supramolecular organization of compressed ethylene gas in supercritical conditions are recognized in infrared spectra.
Almost 60 years have passed since K. Ziegler and G. Natta shared the Nobel Prize for the discovery of olefin polymerization by transition metals. G. Natta proposed and E. Arlman and P. Cossee elaborated the insertion mechanism (IM), which has been generally accepted. However, IM has generated many open questions.
In the previous six decades almost...
Недавно је група научника из Америке постигла напредак у разумевању структуре течности и компресованих гасова. Показало се да су њихови резултати у сагласности с нашим, до којих смо дошли пре четрдесет година. Овде смо описали оне путоказе и начела који су нас довели до нашег поимања надмолекулске структуре и фазних стања гасова и течности у над-и...
Gases and liquids at sub-and super-critical conditions consist various (supra)molecular particles - single molecules and molecular pairs, bimolecules and oligomolecules - which contribute to different phase states in fluids. Here we describe the guides and principles that led us to our comprehensions. Special attention was paid to those people whos...
Banuti D.T. et al. discuss properties of supercritical and real fluids, following the overarching question: "What is a supercritical fluid?" They put seven crucial questions and give the relevant answers which suggest them to make a revised diagram of supercritical state. The aim of our comments is to analyze their main findings and to compare them...
Experimental evidences for three phase transitions in supercritical ethylene have been presented:
(1) Ideal gas to Alpha phase at Vm=2Vc corresponds to transition of single 3D rotating molecules to 3D rotating molecular pairs;
(2) Alpha to Beta phase at critical isochore (V/Vc=1, i.e. Widom line) corresponds to 3D rotating molecular pairs transiti...
Experimental data presented by van der Molen and by Cudby confirmed our hypothesis that ethyl branches arise presumably by copolymerization of ethylene with 1-butene obtained by thermal dimerization of ethylene molecules. The dimerization occurs in situ within the molecular pairs which exist in beta phase, and not in gamma phase of compressed ethyl...
It is generally accepted that a macromolecule is formed by consecutive addition of a single monomer molecule to a growing chain. It is considered as an independent event, i.e. the surrounding molecules do not participate. In liquid, compressed gaseous and adsorbed monomers, however, there are clusters of molecules which behave as single physical an...
The conformations and interactions of macromolecules chains are scrutinized by the comprehensions of R. Boscovich, G. W. F. Hegel and F. Engels on the attraction and repulsion as the essential properties of matter. It was shown that an intermolecular attraction (or repulsion) of polymer chains are compensated by intramolecular repulsion (or attract...
In part II /Svet polimera, 19(3)130-133(2016)/ we considered the criteria for distinguishing higher and lower forms of matter motion. We have shown that the motion of the macromolecular chain as a whole is new and highest form of motion that characterize the macromolecular level of matter, but the movement of the chain segments is a lower form. In...
In the part I of the research /Svet polimera, 19(2)77¬82(2016)/ we considered the attraction and repulsion in macromolecules formation according to the usual interpretation of polymerization and polycondensation, and also in DNA replication. In this part II, we consider the criteria for distinguishing higher and lower forms of motion of atoms, mole...
Our recently published article "Attraction and repulsion as the essence of matter - from ancient philosophy to modern science" /Annals of the Branch of SANU in Novi Sad, No. 11,58-69 (2015)/ has shown that in ancient and classical philosophy there is an comprehension that attraction and repulsion are the essence of matter. However, in that previous...
Liquid vinyl monomers consist of two microphases: a discrete disordered phase (contains rotating bimolecules which molar volume is equal to van der Waals constant b) is dispersed in a continuous ordered phase (contains rotating oligomolecules which molar volume is equal to that of solid phase at triple point). Kinetics of free radical polymerizatio...
Olefins were polymerized by Al(i-Bu)3 and TBAF supported on SiO2 and other inorganic supports. Ionic species were proposed:
Al(i-Bu)3 +TBAF ----> [Al(i-Bu)2](+) (positively charged) + [TBAF-iBu](-) (negatively charged)
These ionic species increased activity hunderd times after the addition of supports. The highest surprise was that the HIGH ISOTAC...
W. Hirahata presented that ethylene, propylene and 1-hexene could polymerize in the presence of Al(i-Bu)3 and TBAF which reacted producing ionic species:
Al(i-Bu)3 +TBAF ---> [Al(i-Bu)2](+) (positively charged) + [TBAF-iBu](=) (negatively charged)
These ionic species alone have low activity. After the addition of SiO2 (or some other inorganic supp...
In cited article propylene was polymerized using TiCl4/DiBP/MgCl2 catalyst activated by triisobutylaluminum (TiBA) solution in n-heptane. The effects of TiBA concentrations on polymerization kinetics, PP yield, Mn, MWD and stereoregularity have been investigated. The aim of our comments is to explain the experimental these results by Charge Percola...
In cited article, the experiments of free radical dispersion polymerization of ethylene were preformed in multi-component system (water, clay Laponite-RD, ethylene…) at 210-270 bars and 60-105 deg. C. In our previous articles we presented a model of supramolecular organization and phase states of compressed ethylene gas and used it to interpret fre...
At low pressure ethylene gas consists of single translating and rotating molecules and behaves as ideal gas. With decrease of free volume by compression, various rotating supramolecular particles are formed which require less space for the movement: molecular pairs, bimolecules and oligomolecules. The appearance of a new kind of particles is manife...
Frenkel line is a dynamic transition between rigid liquid and nonrigid liquid (gaslike) states. Based on the experimental results for methane presented in relevant article [1], we confirmed that crossover at 298 K and 100 MPa is very close to critical isentrope line S/Sc=1. Also, the observed crossovers at 345 K and 374 K, at higher pressures, are...
The experimental observations of liquid-liquid phase transitions in ethane at 300 K are interpreted by supramolecular structure of fluids based of Roger Boscovich’s (1711-1778) comprehensions.
Dialectical foundations of supramolecular organization and polymerization of monomers includes a study of macromolecular segmental movements origin and the opposites of: necessary vs. available space for particles movement; attraction vs. repulsion; order vs. disorder; homogeneity vs. heterogeneity; continuity vs. discontinuity; necessity vs. coinc...
Dialectical foundations of supramolecular organization and polymerization of monomers includes a study of macromolecular segmental movements origin and the opposites of: necessary vs. available space for particles movement; attraction vs. repulsion; order vs. disorder; homogeneity vs. heterogeneity; continuity vs. discontinuity; randomness and dete...
According to Greek philosopher Empedocles' comprehensions the attraction and repulsion contribute to self-organization of a system of elements. We illustrated it by DNA replication and by olefins adsorption on supports. Olefins polymerizations by Ziegler-Natta, Phillips and metallocene complexes are interpreted by charge percolation mechanism.
Comonomer content in copolymer and comonomer effect on catalyst activity were explained by monomers co-adsorption on catalyst support. Computer simulations based on Charge Percolation Mechanism of olefin polymerization were performed to interpret the published experimental data for ethylene/propylene copolymerization by various catalysts including...
According to Greek philosopher Empedocles’ comprehensions the attraction and repulsion contribute to self organization of a system of elements. We illustrated it by DNK replication and by olefins adsorption on supports. Olefins polymerizations by Ziegler-Natta, Phillips and metallocene complexes are interpreted by charge percolation mechanism.
The experimental data [1,2] on the effects of several organohalide compounds and Al/Ti molar ratio on TiCl4/MgCl2 catalyst for ethylene polymerization are explained by Charge percolation mechanism (CPM).
[1] Bahri-Laleh N., Arabi H, Mehdipor-Ataei S, Nekoomanesh-Haghighi M., Zohuri G., Seifali M., Akbari Z, “Activation of Ziegler-Natta Catalysts by...
Liquid vinyl monomers consist of two microphases: a discrete disordered phase (contains rotating bimolecules which molar volume is equal to van der Waals constant b) is dispersed in a continuous ordered phase (contains rotating oligomolecules which molar volume is equal to that of solid phase at triple point). Kinetics of free radical polymerizatio...
Modern physics has the problem of singularities which are zero dimensional points in space which when assigned mass then have infinite density, and this leads to the difficulty of not knowing how to handle infinity. However, in the conception of Boscovich’s theory an object can be treated as if all its mass were at its centre of gravity, effectivel...
Roger Boscovich, History of science, Natural philosophy, particle interaction. intermolecular forces, Leon Lederman, Atom discovery; Theory of natural philosophy; Quantum theory; macromolecules interaction; nano particles interaction; Niels Bohr
The scope of work of P. Aigner et al. was to synthesize various MgCl2-supported Ziegler–Natta catalysts [using different Mg(OR)2/EtAlCl2 ratio, heptanes washing procedure, additional EtAlCl2 and TiCl4 titanation temperature] with the intention to influence polymerization performance: polymerization rate, catalysts activity, polymer molecular mass a...
It is generally accepted in polymer science that a macromolecule is formed by consecutive addition of a single monomer molecule to a growing chain. It is considered as an independent event, i.e. the surrounding molecules do not participate. In liquid, compressed gaseous and adsorbed monomers, however, there are clusters of molecules which behave as...
Boscovich (1711-1787) differentiates between absolute and relative movements. He described the relative movements of two bodies by parallel, crosswise and passing over (evading) paths. In this work, we present the mathematical expressions for the relative rates of two bodies moving at constant rate in parallel and crosswise trajectories. It follows...
Roger Boscovich (1711-1787) described the relative movements of two bodies by parallel, crosswise and passing over (evading) paths. In this work, we present the mathematical expressions for the relative rates of two bodies moving at constant rate in parallel and crosswise trajectories. It follows, however, that relative velocities are not constant...
The conformations and interactions of macromolecules chains are scrutinized by the comprehensions of R. Boscovich, G. W. F. Hegel and F. Engels on the attraction and repulsion as the essential properties of matter. It was shown that an intermolecular attraction (or repulsion) of polymer chains are compensated by intramolecular repulsion (or attract...
U drugom delu istraživanja /Svet polimera, 19(3)130–133(2016)/ razmatrali smo kriterijume za razlikovanje viših i nižih oblika kretanja materije. Pokazali smo da je kretanje makromolekulskog lanca kao celine taj novi i najviši oblik kretanja kojim se odlikuje makromolekulski nivo materije, a da je kretanje segmenata lanca niži oblik. U ovom trećem...
In 2014 we presented our research titled „Was Tesla photographed while reading Boscovich's theory?”. Namely, the photographs of Nikola Tesla, sitting in a chair and reading some book, have been presented very often in scientific, professional and popular literature, newspaper articles, at television and at Internet. It is stated that the book is "T...
In 2014 we presented our research titled "Was Tesla photographed while reading Boscovich's theory?”. Namely, the photographs of Nikola Tesla, sitting in a chair and reading some book, have been presented very often in scientific, professional and popular literature, newspaper articles, at television and at Internet. It is stated that the book is "T...
Derivation of mathematical expressions for the kinetics of adsorption is shortly presented in book "Surface Science". Reading this excellent book (first edition published in 2002) we noticed that there was some disagreement between adsorption kinetics presented inthe book and our results of adsorption simulation by computer. A more detailed analysi...
In this article authors present the very sophisticated experimental techniques and high skill in the interpretation of redox processes in Phillips Cr/SiO2 leading to active centers for initiation of ethylene polymerization. The experimentally determined ethylene uptake was C/Cr ratio = 1.9±0.2. In our comments we supported their findings and interp...
In the relevant article, the kinetics of ethylene polymerization was studied on both standard Cr/SiO2 Phillips catalyst and catalyst oxidized by N2O. The purpose of our comments is to support the findings and results in the article and to interpret them by Charge Percolation Mechanism (CPM) of olefin polymerization by Ziegler-Natta, metallocene and...
In the article the adsorption, reaction and desorption of ethylene, 1-hexene or cyclohexene on Cr(VI)/SiO2 containing 1 or 3 wt.% chromium were monitored by thermogravimetry, differential scanning calorimetry and mass spectrometry. Polymer yield and rate of polymerization by model and industrial catalysts were reported. The aim of our comments is t...
The catalytic activity of two Cr(II)/SiO2 samples obtained after two different controlled annealing procedures are discussed and compared. These samples are characterized by a different relative population of the families of Cr(II) sites present on the silica surface and by a different catalytic activity toward ethylene polymerization. The purpose...
In relevant articles a standard Philips catalyst (CrPHL) and modified with SiH4 (CrSiH4) and SiEt3H (CrTES) were investigated by several spectroscopic methods and used to polymerize ethylene. The results of experiments include: induction period, polyethylene (PE) yield, molecular mass and distribution, oligomeric alpha-olefins formation and their c...
Authors of relevant articles investigated titanium-magnesium catalysts with a low titanium content (below 0.1 wt%) activated by triethylaluminum, triisobutylaluminum and trimethylaluminum. The compounds with a high concentration of isolated Ti(3+) ions were produced. Authors claimed that for the first time a correlation between the content of isola...
Nikolaeva M. et al. investigated the effect of AlEt3 and external donor (propyltrimetoxysilane) on propylene polymerization using two concentration of Ti on MgCl2 (0.1 and 3.5 wt. %). The experimental results include: PP yield, PP fraction soluble in o-xylene, Mn, Mw, Mw/Mn as well as PP fractionation, stereoregularity and melting of PP fractions....
The scope of work of P. Aigner et al. [1] was to find the optimal precontacting time of Ziegler-Natta catalyst (TiCl4 supported by MgCl2) and cocatalyst (triethylaluminium) for industrial ethylene copolymerization processes. Authors investigated the influence of precontacting mixing of catalyst and cocatalyst on ethylene slurry homopolymerization a...
Olefin polymerizations by transition metal (Mt) complexes were discovered in 1953. Nowadays, they are the most important industrial processes for the production of polyethylene, polypropylene and other plastic material. It is generally accepted that the polymerization occurs by insertion of olefin molecules between Mt active center and growing poly...
U prvom delu istraživanja /Svet polimera, 19(2)77¬82(2016)/ razmatrali smo atrakciju i repulziju pri nastajanju makromolekula prema uobičajenom tumačenju polimerizacije i polikondenzacije, a takođe i pri replikaciji DNK. U drugom delu razmatramo kriterijume za razlikovanje viših i nižih oblika kretanja atoma, molekula i makromolekula: strukturno-ge...
Authors of article found that Frenkel line was between Widom line (calculated from the maximum of heat capacity) and Melting line. They observed structural crossover to the Frenkel line separating liquid-like and gas-like states of supercritical matters. In our comments we presented that our published data concerning Frenkel and Widom lines in cupe...
Questions
Question (1)
Definition of catalyst
Definition of catalysis is: "By catalysis is meant the change in the rate of a chemical reaction under the action of substances that do not change chemically as a result of the reaction. These substances are called catalysts".
Now we will consider two examples taken from the literature. To prevent you to fall into the usual prejudices, we replaced the names of individual chemical components with codes E, X, Y and Z.
Example 1(a): "X/Y was the first ... used for E polymerization. The ... activity decayed rapidly due to reduction of X so X/Y has a very poor activity. By using Z in place of Y, it was observed a 1000-fold increase in E polymerization activity". Similarly, example 1(b): "X in combination with ... Y ... are indeed capable to polymerize E, but only at very low activity. Only with the ... application of Z ... it is possible to enhance the activity, surprisingly by a factor of 10000".
Question: Having in the mind the definition of catalysis and the behavior of components E, X, Y, and Z in examples 1(a) and 1(b), what is the catalyst: E, X, Y, or Z?