Catalyst components for the(co)polymerization of ethylene comprising Ti, Mg, halogen, ORI groups, where RI is a C1-C12 hydrocarbon group optionally containing heteroatoms, having ORI/Ti molar ratio in the range 0.1-1.5, a Mg/Ti molar ratio of less than 8, an amount of titanium, with respect to the total weight of said solid catalyst component, higher than 4% by weight characterized by a specific SS-NMR pattern are particularly useful for preparing narrow MWD crystalline ethylene polymers.

Catalyst components for the polymerization of olefins

A heterogeneous catalyst component obtainable by contacting: (a) a solid Lewis acid of formula MR1a wherein M is a metal of group 1-12 of the Periodic Table of the Elements; R1 is a fluorine, chlorine, bromine or iodine atom; and a is equal to the valence of the metal M; and (b) at least one ionic compound of formula (I) [((T)pR2)nMl(R3)m]-[D]+ (I) wherein: MI is an element belonging to group 13 of the Periodic Table of the Elements; R3, equal to or different from each other, are halogen atoms, halogenated C6-C20 aryl and halogenated C7-C20 alkylaryl groups; two R1 groups, can also form with the element M one condensed ring; R2, equal to or different from each other, are hydrocarbon groups; T is a Lewis base in its neutral form; n ranges from 1 to 4; m ranges from 0 to 3; and m+n= 4; p ranges from 1 to 10; and [D]+ is a monovalent cation.

Catalyst system for the polymerization of olefins

A speaker apparatus in which the acoustic sound is radiated by flexural oscillations of a diaphragm in the form of a panel having a substantially flat surface. The speaker apparatus includes a panel-shaped diaphragm the outer rim of which can be oscillated substantially freely at least in the direction along the diaphragm thickness and at least one driver unit constituting an oscillation source secured to the diaphragm surface for imparting oscillations to the diaphragm. The diaphragm is set into flexural oscillations by oscillations applied from the driver unit driven on the basis of the playback input signal. By flexurally oscillating the diaphragm to radiate the acoustic sound, optimum frequency response characteristics can be obtained over a wide frequency range from the low to high frequency range. Moreover, the acoustic sound of optimum sound quality may be radiated in a state of minimum sound pressure level fluctuations over a frequency range from the low to high frequency range.

Speaker apparatus and electronic apparatus having speaker apparatus enclosed therein

The present invention relates to an adduct comprising MgC12, an alcohol (ROH) in which R is a C 1-C 10 hydrocarbon group, and a compound containing a transition metal M selected from the Groups 3 to 11 or the lanthanide or actinide groups of the Periodic Table of the Elements (new IUPAC version) in an amount such as to give a weight of M atoms lower than 10% based on the total weight of the adduct. The catalyst components that are obtained by reacting the adducts with halogenating agents show very high specific activity.

Magnesium dichloride-alcohol adducts and catalyst components obtained therefrom

A solid catalyst component for olefin polymerization which is prepared through contact among a magnesium compound, a titanium compound, and an electron-donating compound and has a parameter, S1/S2, determined by Raman spectrometry of 0.5 to 10 (wherein S1 and S2 are values determined by Raman spectrometry and mean the peak area for the highest peak in the 360-520 cm-1 range and the peak area for the highest peak in the 160-340 cm-1 range, respectively). A catalyst comprising this solid catalyst component, an organoaluminum compound, and an organosilicon compound has an excellent activity against hydrogen and can yield a highly stereoregular olefin polymer in a high yield.

Solid catalyst component for olefin polymerization and catalyst

A solid catalyst component comprising Ti, Mg, halogen and a couple of monofunctional electron donor compounds MD1 and MD2 selected from esters and ethers, said donors being present in amounts such that the molar ratio MD1/MD2 ranges from 20 to 800. The so obtained catalyst component when converted into a catalyst is able to produce ethylene polymers with good morphological properties even under drastic polymerization conditions.

Catalyst Components for the Polymerization of Olefins and Catalysts Therefrom Obtained

Components of catalysts for the polymerization of olefins are ob tained by contacting a Ti compound of formula Ti(OR)n-yXy, where n is the valence of titanium and y is a number between 1 and n, with a pre-polymer having a porosity higher than 0.3 cc/g and containing from 0.5 to 100 g of polymer per g of solid catalyst component, the pre-polymer being obtained by (co)polymerizing an olefin or a diolefin in the presence of a catalyst comprising a Ti, V, Zr of Hf compound supported on an Mg dihalide having a mean crystallite dimension lower than 30 nm.

Pre-polymerized catalyst components for the polymerization of olefins

A process for the (co)polymerization ethylene, optionally in mixtures with olefins CH=CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, carried out in the presence of a catalyst system comprising (A) a solid catalyst component which comprises Mg, halogen an electron donor selected form ethers, esters, or amines, and Ti atoms in an oxidation state such that the weight percentage ratio between Ti(red)/Ti?(tot)? ranges from about 0.05 to about 1; wherein Ti?(red)? is the weight percentage on the solid catalyst component of the Ti atoms having a valence less than 4 and Ti?(tot)? is the weight percentage on the solid catalyst component of all the Ti atoms and (B) an Al-alkyl compound. The said process is capable to produce ethylene polymers with a reduced oligomers content and/or improved mechanical characteristics.

Process for the (co)polymerization of ethylene

Solid Lewis adducts comprising MgCl2, a Lewis base (LB) belonging to ethers, esters, ketones, silanes or amines and an alcohol ROH, in which R is a C 1-C 15 hydrocarbon group optionally substituted with heteroatoms containing groups, which compounds are in molar ratios to each other defined by the following formula MgC12(ROH) m(LB)n in which m ranges from 0.05 to 6, n ranges from 0.08 to 6. These adducts allow to prepare catalysts having a good morphological stability and high polymerization activities.

Magnesium dichloride-based adducts and catalyst components obtained therefrom

The present invention relates to a slurry process for preparing an ethylene polymer having a melt flow ratio F/P, which is the ratio among the melt index value measured according to ASTM 1238 condition "F" and the melt index value measured according to ASTM 1238 condition "P" of equal to or lower than 27, carried out in two or more stages of polymerization at temperatures in the range from 60 to 120°C, in which at least two of the said two or more polymerization stages are carried out under different amounts of molecular weight regulator, said process being carried out in the presence of (A) a solid catalyst component comprising Ti, Mg, halogen, having a porosity (PF), measured by the mercury method and due to pores with radius equal to, or lower than, 1µm, of at least 0.3 cm 3 /g and a surface area determined by BET method, of lower than 100 m 2 /g, and being further characterized by the fact that more than 50% of the titanium atoms are in a valence state lower than 4 and (B) of an organoaluminum compound.

Multistage Process for the Polymerization of Ethylene

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Diego Brita

Author Tools

Chat about Author