scholarly journals Polymerization of Ethylene in the Presence of Various Ligand Organometallic Catalytic Systems

2020 ◽  
pp. 31-40
Author(s):  
Qanbarli Zeynab ◽  
Khanmetov Akber ◽  
Azizbeyli Hemide ◽  
Khamiyev Matlab
Keyword(s):  
Ionic Liquid ◽  
Ethylene Polymerization ◽  
The Other ◽  
Polymerization Process ◽  
Catalytic Systems ◽  
Zirconium Complexes ◽  
Other Hand ◽  
Physicochemical Methods ◽  
Liquid Type

This work presents the results on the preparation of new readily available zirconium-containing arylimine complex catalytic systems and their application together with metallocenes in ethylene polymerization. For this purpose, zirconium complexes with grafted ionic liquid type ligands were synthesized and tested in the ethylene polymerization process. On the other hand, it is known that one of the main industrial catalysts for the polymerization process of ethylene is dicycopentadienyl titanium and zirconium dichloride. Therefore, one of the main objectives of the work is to test the using of the newly synthesized complexes with the industrial Cp2TiCl2 catalyst. The products obtained were identified by various physicochemical methods and it was found that these catalytic systems allow one to control the structure and composition of the products obtained.

Ionic Liquid Promoted Regio- and Stereo-Selective Thiolysis of Epoxides—A Simple and Green Approach to β-Hydroxy- and β-Keto Sulfides

2007 ◽  
Vol 60 (4) ◽  
pp. 278 ◽  
Author(s):  
Brindaban C. Ranu ◽  
Tanmay Mandal ◽  
Subhash Banerjee ◽  
Suvendu S. Dey
Keyword(s):  
Ionic Liquid ◽  
Organic Solvent ◽  
The Other ◽  
Green Approach ◽  
Other Hand ◽  
Basic Ionic Liquid ◽  
Epoxy Ketones ◽  
Stereo Selectivity

A variety of epoxides underwent facile cleavage by thiols under the catalysis of 1-methyl-3-butylimidazolium bromide, [bmIm]Br, to produce the corresponding β-hydroxy sulfides with high regio- and stereo-selectivity. On the other hand, a specially designed basic ionic liquid, [bmIm]OH, efficiently catalyzes the thiolysis of α,β-epoxy ketones providing β-keto sulfides through simultaneous retro-aldol cleavages. The reactions are clean, high yielding, and do not require any organic solvent. The catalyst is also recycled.

“Naked” S2O72– ions – the serendipitous formation of the disulfates [HPy]2[S2O7] and [bmim][HPy][S2O7] (HPy = pyridinium; bmim = 1-Butyl-3-methylimidazolium)

2015 ◽  
Vol 70 (1) ◽  
pp. 3-8
Author(s):  
Jörn Bruns ◽  
Christian Logemann ◽  
Alexander Weiz ◽  
Claudia Kolb ◽  
Mathias S. Wickleder
Keyword(s):  
Crystal Structure ◽  
Ionic Liquid ◽  
Charge Compensation ◽  
The Other ◽  
Side Product ◽  
Other Hand

Abstract[bmim][HPy][S2O7] [monoclinic, P21/n, Z = 4, a = 825.78(2), b = 1545.30(3), c = 1410.80(3) pm, β = 104.726(1)°, V = 1741.16(7) Å3] was obtained as a side product in the reaction of GeCl4, oleum (65% SO3), and the pyridine (Py) complex Py·SO3 in the ionic liquid 1-butyl-3-methylimidazolium hydrogensulfate, [bmim][HSO4], at 50 °C. Charge compensation of the disulfate ion is achieved by the counterions pyridinium, [HPy]+, and 1-butyl-3-methylimidazolium, [bmim]+. The crystal structure shows alternating layers of [bmim]+ cations on one hand and [HPy]+ cations and disulfate anions on the other hand. Pyridinium disulfate, [HPy]2[S2O7] [orthorhombic, P212121, Z = 4, a = 801.35(1), b = 1257.62(2), c = 1357.22(3) pm, V = 1367.80(4) Å3] was formed unexpectedly in the reaction of Eu2O3 and Py·SO3 in pyridine. The crystal structure exhibits a layer-like arrangement of disulfate and pyridinium moieties in the ab plane. In both compounds, the disulfate groups are essentially uncoordinated allowing for a detailed inspection of “naked” S2O72– ions.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Don’t Put Me in This Group

2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke
Keyword(s):  
Positive Emotions ◽  
Negative Emotions ◽  
Negative Information ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Group Memberships

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.

ON THE OTHER HAND

1961 ◽  
Vol 6 (6) ◽  
pp. 222-223
Author(s):  
Edwin G. Boring
Keyword(s):  
The Other ◽  
Other Hand
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