Cationic Polymerization of 1,3-Pentadiene Initiated by Aluminum Chloride: Determination of the Various Side Reactions

1998 ◽  
Vol 31 (22) ◽  
pp. 7627-7635 ◽  
Author(s):  
Fabienne Duchemin ◽  
Véronique Bennevault-Celton ◽  
Hervé Cheradame ◽  
Claude Mérienne ◽  
Anne Macedo
Keyword(s):  
Aluminum Chloride ◽  
Cationic Polymerization ◽  
Side Reactions ◽  
Chloride Determination

CATIONIC COPOLYMERIZATION OF ISOBUTYLENE WITH ISOPRENE: KINETICS OF THE PROCESS AND DETERMINATION OF KINETIC CONSTANTS

2015 ◽  
Vol 88 (4) ◽  
pp. 574-583 ◽  
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenco ◽  
D. A. Shiyan ◽  
G. E. Zaikov
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Methyl Chloride ◽  
Theoretical Description ◽  
Kinetic Constants ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization ◽  
Kinetics Of

ABSTRACT A theoretical description has been developed of the kinetics of isobutylene with isoprene (IIR) cationic polymerization in the environment of methyl chloride on aluminum trichloride as the catalyst. Based on experimental data on the kinetics of copolymerization (isobutylene conversion curve) and the molecular weight characteristics of the copolymer of IIR, kinetic constants for the process were found. Adequacy of the developed theoretical description of the kinetics of the IIR copolymerization process was confirmed by comparing the experimental molecular-weight characteristics calculated by this description, independent characteristics, and IIR unsaturation.

DEVELOPMENT OF A METHOD FOR QUANTITATIVE DETERMINATION OF THE AMOUNT OF FLAVONOIDS IN TRIPLEUROSPERMUM INODORUM’S FLOWERS

2021 ◽  
pp. 157-166
Author(s):  
Blinova O.L. ◽  
Gileva A.A. ◽  
Hlebnikov A.V. ◽  
Belonogova V.D. ◽  
Turyshev A.Y.
Keyword(s):  
Quantitative Determination ◽  
Aluminum Chloride ◽  
Chloride Solution ◽  
Uv Spectra ◽  
Raw Material ◽  
Spectral Studies ◽  
Scientific Medicine ◽  
Differential Spectrophotometry ◽  
The Stability

Chamomilla recutita is used in scientific medicine. Tripleurospermum inodorum (L.) Sch. Bip. is widely spread among possible impurities of Chamomilla recutita (L.) Rauschert. This plant is perspective for establishment into scientific medicine but it can’t change Chamomilla recutita (L.) Rauschert. Purpose of research: development of a method for the quantitative determination of the amount of flavonoids in terms of rutin in Tripleurospermum inodorum’s flowers using differential spectrophotometry. Materials and methods. The samples prepared in different parts of Russia were used as objects of research. (2017 – 2020). Spectral studies were carried out in the wavelength range of 350-430 nm with a step of 1 nm using a spectrophotometer SF-2000. Results. To determine the analytical wavelength, the UV spectra of alcohol extraction of Tripleurospermum inodorum’s flowers were studied. Maximum of absorption was noticed at wavelength 370 nm. The differential spectrum of the same extraction with an aluminum chloride solution of 2% in 96% alcohol has a maximum at a length of 410±2 nm, which coincides with the maximum of the Standard Sample (SS) of rutin. The largest number of flavonoids is extracted by 70% alcohol. The maximum optical density and the highest output of the number of flavonoids from the raw material is observed at a degree of grinding of 2 mm with a single extraction for 60 minutes. In the conditions of complexation, the optimal ratio of the volume of the test solution and aluminum chloride with a solution of 2% in 96% alcohol is the ratio of 1:1. The stability of the complex with an aluminum chloride solution of 2% in 96% alcohol is observed in 40 minutes after the start of the reaction and retains it for 30 minutes. Findings. The method is developed and the parameters of the quantitative determination of the amount of flavonoids in Tripleurospermum inodorum flores are determined in terms of rutin using differential spectrophotometry.

Thin Layer Chromatographic Method for Determination of Deoxynivalenol in Wheat: Collaborative Study

1986 ◽  
Vol 69 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Robert M Eppley ◽  
Mary W Trucksess ◽  
Stanley Nesheim ◽  
Charles W Thorpe ◽  
Albert E Pohland ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Aluminum Chloride ◽  
Chloride Solution ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Sample Extraction ◽  
Layer Chromatography

Abstract A collaborative study of a rapid method for the determination of deoxynivalenol (DON) in winter wheat was successfully completed. The method involves sample extraction with acetonitrile-water (84 + 16), cleanup using a disposable column of charcoal, Celite, and alumina, and detection by thin layer chromatography after spraying with an aluminum chloride solution. Each of the 15 collaborators analyzed 12 samples, 2 of which were naturally contaminated, and 10 to which DON was added, in duplicate, at levels of 0,50,100,300, and 1000 ng/ g. Average recoveries of DON ranged from 78 to 96% with repeatabilities of 30-64% and reproducibilities of 33-87%. The results of the study show that false positives were not a problem and that all of the analysts could detect DON at the 300 ng/g level or higher. The method has been adopted official first action.

Comparison of Laboratory Techniques for the Determination of Pesticide Residues in Milk

1963 ◽  
Vol 46 (2) ◽  
pp. 209-215
Author(s):  
J Lloyd Henderson
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Pesticide Residues ◽  
Colorimetric Method ◽  
Laboratory Techniques ◽  
Test Electron ◽  
Chloride Determination ◽  
Low Levels ◽  
Organic Chloride

Abstract Of the techniques available for specific pesticide residues, fly bioassay is non-specific and not very sensitive; total organic chloride determination also lacks specificity; the AOAC colorimetric method produces variable results, lacks sensitivity for low levels of residues, and does not cover the range of residues likely to be present in milk. Chromatographic tests are most satisfactory. Microcoulometric gas chromatography has many advantages but requires a skilled analyst. Electron-capture gas chromatography is promising but has not been fully developed. The Mills test, which combines column cleanup with identification by paper chromatography, is a rapid, practical screening test. In a collaborative comparison of the chromatographic procedures, microcoulometry tended to give higher results than the Mills test; electron-capture gave lower results than the other two methods. Details of all tests must be followed closely for good results.

scholarly journals New way of anionic ring-opening copolymerization of β-butyrolactone and ε-caprolactone: determination of the reaction course

2020 ◽  
Vol 27 (12) ◽  
Author(s):  
Zbigniew Grobelny ◽  
Justyna Jurek-Suliga ◽  
Sylwia Golba
Keyword(s):  
Ring Opening ◽  
Chemical Structure ◽  
Side Reactions ◽  
Complexing Agent ◽  
Critical Approach ◽  
Anionic Ring ◽  
Tetrahydrofuran Solution ◽  
End Group ◽  
C Nmr

Abstract Poly(ε-caprolactone)-block-poly(β-butyrolactone) copolymers were prepared in two-step synthesis. Firstly, poly(ε-caprolactone) (PCL) was obtained by anionic ring-opening polymerization of CL initiated with anhydrous KOH activated 12-crown-4 cation complexing agent. Reaction was carried out in tetrahydrofuran solution and argon atmosphere at room temperature. Then, β-butyrolactone (BL) and 18-crown-6 were added to the system, resulting in PCL-block-PBL copolymer, which contains after methylation hydroxyl starting group and methyl ester end group. The main product was contaminated with PCL and PBL homopolymers formed in a side reactions. 13C NMR technique was used for determination of chemical structure of polymers obtained. The course of the studied processes was proposed. MALDI-TOF technique was used to reveal the macromolecules’ architecture where several series were found. The identified series shown that mainly copolymeric macromolecules were formed with scare contribution of homopolymeric polybutyrolactone with trans-crotonate starting groups and polycaprolactone, which is congruent with the proposed reaction mechanism. Moreover, critical approach concerning previously reported PCL-block-PBL copolymer synthesis by use of NaH as initiator was also presented.

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