scholarly journals Real-time analysis of methylalumoxane formation

2021 ◽  
Author(s):  
Anuj Joshi ◽  
Harmen S. Zijlstra ◽  
Elena Liles ◽  
Carina Concepcion ◽  
Mikko Linnolahti ◽  
...  
Keyword(s):  
Real Time ◽  
Time Analysis ◽  
Esi Ms ◽  
Real Time Analysis ◽  
Rapid Formation ◽  
Hydrolysis Of

The activator methylaluminoxane is made by hydrolysis of trimethylaluminum. Analysis using ESI-MS reveals rapid formation of small oligomers is followed by slower aggregation to the larger precursors most capable of releasing [Me2Al]+.

scholarly journals Enzymatic Hydrolysis of Polyester Thin Films: Real-Time Analysis of Film Mass Changes and Dissipation Dynamics

2015 ◽  
Vol 50 (1) ◽  
pp. 197-206 ◽  
Author(s):  
Michael Thomas Zumstein ◽  
Hans-Peter E. Kohler ◽  
Kristopher McNeill ◽  
Michael Sander
Keyword(s):  
Thin Films ◽  
Enzymatic Hydrolysis ◽  
Real Time ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Hydrolysis Of

scholarly journals Real-time analysis of Pd2(dba)3 activation by phosphine ligands

2017 ◽  
Vol 53 (5) ◽  
pp. 854-856 ◽  
Author(s):  
Eric Janusson ◽  
Harmen S. Zijlstra ◽  
Peter P. T. Nguyen ◽  
Landon MacGillivray ◽  
Julio Martelino ◽  
...  
Keyword(s):  
Real Time ◽  
Active Species ◽  
Phosphine Ligands ◽  
Time Analysis ◽  
Esi Ms ◽  
Real Time Analysis ◽  
Insight Into

Real-time UV-Vis/ESI-MS monitoring of Pd2(dba)3 activation provides insight into active species and the effect of activation protocol on their formation.

scholarly journals Real-Time Analysis of Methylalumoxane Formation

2020 ◽  
Author(s):  
Anuj Joshi ◽  
Harmen S. Zijlstra ◽  
Elena Liles ◽  
Carina Concepcion ◽  
Mikko Linnolahti ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Real Time ◽  
Complex Mixture ◽  
Activation Process ◽  
Ionization Mass ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Sheet Structure ◽  
Industrial Samples ◽  
Hydrolysis Of

<p>Methylalumoxane (MAO), a perennially useful activator for olefin polymerization precatalysts, is famously intractable to structural elucidation, consisting as it does of a complex mixture of oligomers generated from hydrolysis of pyrophoric trimethylaluminum (TMA). Electrospray ionization mass spectrometry (ESI-MS) is capable of studying those oligomers that become charged during the activation process. We’ve exploited that ability to probe the synthesis of MAO in real time, starting less than a minute after the mixing of H<sub>2</sub>O and TMA and tracking the first half hour of reactivity. We find that the process does not involve an incremental build-up of oligomers; instead, oligomerization to species containing 12-15 aluminum atoms happens within a minute, with slower aggregation to higher molecular weight ions. The principal activated product of the benchtop synthesis is the same as that observed in industrial samples, namely [(MeAlO)<sub>16</sub>(Me<sub>3</sub>Al)<sub>6</sub>Me]<sup>–</sup>, and we have computationally located a new sheet structure for this ion 94 kJ mol<sup>-1</sup> lower in Gibbs energy than any previously calculated.</p>

scholarly journals Real-Time Analysis of Methylalumoxane Formation

2020 ◽  
Author(s):  
Anuj Joshi ◽  
Harmen S. Zijlstra ◽  
Elena Liles ◽  
Carina Concepcion ◽  
Mikko Linnolahti ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Real Time ◽  
Complex Mixture ◽  
Activation Process ◽  
Ionization Mass ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Sheet Structure ◽  
Industrial Samples ◽  
Hydrolysis Of

<p>Methylalumoxane (MAO), a perennially useful activator for olefin polymerization precatalysts, is famously intractable to structural elucidation, consisting as it does of a complex mixture of oligomers generated from hydrolysis of pyrophoric trimethylaluminum (TMA). Electrospray ionization mass spectrometry (ESI-MS) is capable of studying those oligomers that become charged during the activation process. We’ve exploited that ability to probe the synthesis of MAO in real time, starting less than a minute after the mixing of H<sub>2</sub>O and TMA and tracking the first half hour of reactivity. We find that the process does not involve an incremental build-up of oligomers; instead, oligomerization to species containing 12-15 aluminum atoms happens within a minute, with slower aggregation to higher molecular weight ions. The principal activated product of the benchtop synthesis is the same as that observed in industrial samples, namely [(MeAlO)<sub>16</sub>(Me<sub>3</sub>Al)<sub>6</sub>Me]<sup>–</sup>, and we have computationally located a new sheet structure for this ion 94 kJ mol<sup>-1</sup> lower in Gibbs energy than any previously calculated.</p>

An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

1976 ◽  
Vol 34 ◽  
pp. 542-543
Author(s):  
R.P. Goehner ◽  
W.T. Hatfield ◽  
Prakash Rao
Keyword(s):  
Electron Diffraction ◽  
Real Time ◽  
Pattern Analysis ◽  
Flow Diagram ◽  
Hard Copy ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Transmission Electron ◽  
One Step ◽  
Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

scholarly journals Real-Time Analysis of Animal Feeding Behavior With a Low-Calculation-Power CPU

2020 ◽  
Vol 67 (4) ◽  
pp. 1197-1205 ◽  
Author(s):  
Yuki Totani ◽  
Susumu Kotani ◽  
Kei Odai ◽  
Etsuro Ito ◽  
Manabu Sakakibara
Keyword(s):  
Feeding Behavior ◽  
Real Time ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Animal Feeding

A threshold-based, real-time analysis in early detection of endpoint anomalies using SIEM expertise

2021 ◽  
Vol 2021 (4) ◽  
pp. 7-16
Author(s):  
Sivaraman Eswaran ◽  
Aruna Srinivasan ◽  
Prasad Honnavalli
Keyword(s):  
Early Detection ◽  
Real Time ◽  
Time Analysis ◽  
Real Time Analysis
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