C21H22O7 (Trans) - Structure No. 1066

2006 ◽  
pp. 1-1
Author(s):  
M. P. Dobhal
Keyword(s):  
Trans Structure

Characterization of the trans-structure in the molecular chain structure of natural rubber

2021 ◽  
pp. 131209
Author(s):  
Zechun Li ◽  
Changjin Yang ◽  
Yanchan Wei ◽  
Yuanbing Zhou ◽  
Shuangquan Liao
Keyword(s):  
Natural Rubber ◽  
Chain Structure ◽  
Molecular Chain ◽  
Trans Structure

Dipole Moments and Molecular Conformation of Allylcarbonylnitrosyl Iron Complexes

1972 ◽  
Vol 27 (11) ◽  
pp. 1316-1319 ◽  
Author(s):  
S. Sorriso ◽  
G. Cardaci ◽  
S. M. Murgia
Keyword(s):  
Molecular Conformation ◽  
Dipole Moments ◽  
Iron Complexes ◽  
Qualitative Comparison ◽  
Formula Group ◽  
Trans Structure

The dipole moments of the complexes π (CH2CXCH2) Fe (CO) (NO) L, with X and L equal, respectively, to H, CO; H, P (C6H5)3; CH3, CO; Cl, CO; Br, CO, have been measured. From the results it is concluded that:1. The value of the group moment is ca. 1.6 D, if = 1.3 D and Co-Fe-CO(NO) =98°.2. A trans structure appears most likely in the π (CH2CYCH2) Fe (CO) 2NO (Y = Cl, Br, CH3).3. Qualitative comparison between and group moments confirms that the C5H5 group bonds to manganese as (C5H5)δ-.

Statistical Lengths of Rubberlike Hydrocarbon Molecules

1943 ◽  
Vol 16 (3) ◽  
pp. 479-485
Author(s):  
Frederick T. Wall
Keyword(s):  
Natural Rubber ◽  
Physical Properties ◽  
Chemical Properties ◽  
Hydrocarbon Chain ◽  
Point Of View ◽  
Double Bonds ◽  
Gutta Percha ◽  
Cis And Trans ◽  
Trans Structure ◽  
And Chemical Properties

Abstract It has been known for some time that the pure hydrocarbons of balata (or gutta-percha) and natural rubber have the same chemical composition and chemical properties. Both balata and rubber appear to be polymers of isoprene, (C5H8)n, with the same degree of unsaturation. Their physical properties are sufficiently different, however, to make it clear that their structures must differ in some important respect. Since the molecules contain numerous double bonds, it has been suggested that rubber and balata are geometric isomers. Every fourth bond in a rubber or balata molecule is a double bond, so it follows that the possibilities for geometric isomerism are considerable. It was proposed by Meyer and Mark that natural rubber hydrocarbon has a structure for which the molecular chain is cis with respect to all of the double bonds. Balata (or gutta-percha) is then supposed to have a trans-structure throughout, this view having been verified by Fuller and Bunn. It is the purpose of the present paper to consider, from the point of view of recent theories of rubber elasticity, to what extent these structures explain the differences in physical properties. The method to be employed involves calculation of the root mean square lengths of the cis- and trans-structures, which, when compared to their maximum lengths, should give an indication of their extensibilities. In 1932 Eyring treated the problem of the average square length of a hydrocarbon chain. In the present paper a different derivation of Eyring's equation is given (for illustrative purposes), after which this derivation will be extended to the rubberlike molecules with double bonds.

Synthesis and Elastomeric Properties of Copolymers of Butadiene and 1,3-Pentadiene

1973 ◽  
Vol 46 (5) ◽  
pp. 1274-1284 ◽  
Author(s):  
A. Carbonaro ◽  
V. Zamboni ◽  
G. Novajra ◽  
G. Dall'Asta
Keyword(s):  
Abrasion Resistance ◽  
Room Temperature ◽  
Composition Range ◽  
General Purpose ◽  
Random Copolymers ◽  
Technological Properties ◽  
Vanadium Compounds ◽  
Catalyst Systems ◽  
Trans Structure ◽  
Aluminum Halides

Abstract Random copolymers of all trans structure have been prepared from butadiene and 1,3-pentadiene, in the presence of vanadium compounds and alkyl aluminum halides composed catalyst systems. Copolymers of butadiene and pentadiene, in the composition range of 30-45 weight per cent of pentadiene, are amorphous at room temperature at rest but crystallize upon stretching. Cured tread stocks show improved technological properties with respect to other synthetic diene-based elastomers. Very good processing and extrusion behavior, high tack, tear strength, and abrasion resistance are outstanding properties of the BP copolymers in the field of general purpose rubbers.

Solid-State 13C NMR Characterization of Irradiation-Cross-Linked Natural Rubber

1987 ◽  
Vol 41 (3) ◽  
pp. 441-446 ◽  
Author(s):  
Dwight J. Patterson ◽  
Jack L. Koenig
Keyword(s):  
Solid State ◽  
Natural Rubber ◽  
Mobile Phase ◽  
Chain Scission ◽  
Structure Changes ◽  
Nmr Characterization ◽  
Cross Links ◽  
Gamma Irradiated ◽  
Trans Structure

Solid-state 13C NMR was used to characterize the structure changes produced in gamma irradiation in natural rubber. The structure of the irradiated natural rubber was found to be heterogeneous, consisting of a mobile phase and a semi-rigid phase. Cis-trans chain isomerization was detected in the mobile phase of the gamma-irradiated samples. The CP/MAS spectra of the more rigid phase contained resonances due to quaternary carbons arising from cross-links and vinyl end groups caused by main chain scission. The calculated values of β and G( X) agreed with earlier published results. Peroxide-cured natural rubber of an equivalent amount of network density showed a higher amount of trans structure than did the gamma-irradiated natural rubber.

Ni(II) Complexes with bis(β-Acylvinyl)amines and (8-Quinolyl-β-acylvinyl)amines

1977 ◽  
Vol 32 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Janusz Dabrowski ◽  
Adam Krówczyński
Keyword(s):  
Elemental Analysis ◽  
Methyl Groups ◽  
Amine Complexes ◽  
Pmr Spectra ◽  
Trans Structure

The title complexes have been obtained and shown by elemental analysis, IR and PMR spectra to be octahedral. The trans structure has been assigned to bis(β-acylvinyl)amine complexes based on magnetic equivalence of geminal methyl groups in appropriately substituted representatives of this group of compounds. The (8-quinolyl-β-acylvinyl)-amine complexes may have either trans or s-cis (meso) configuration.

scholarly journals First-Principles Study of the Reaction between Fluorinated Graphene and Ethylenediamine

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 284
Author(s):  
Jin Tian ◽  
Yuhong Chen ◽  
Jing Wang ◽  
Tingting Liu ◽  
Meiling Zhang ◽  
...  
Keyword(s):  
Energy Barrier ◽  
Density Functional ◽  
Population Analysis ◽  
Reaction Process ◽  
Main Reaction ◽  
Mulliken Charge ◽  
Reaction Energy ◽  
Functional Theory ◽  
Fluorinated Graphene ◽  
Trans Structure

The reaction process between gauche- and trans-structure ethylenediamine (EDA) and fluorinated graphene (CF) was studied based on density functional theory (DFT). Firstly, the reaction between the most stable gauche-structure EDA and CF was discussed. Some of the reaction results were verified in experiment, but the overall reaction energy barrier was higher. Then, the reaction between the trans-structured EDA and CF was simulated, which concluded that CF is reduced in the main reaction channel and HF is generated at the same time. In this reaction process, the reaction energy barrier is as low as 0.81 eV, which indicates that the reaction may occur spontaneously under natural conditions The Mulliken charge population analysis and the calculation of bond energy prove that the NH bond is more stable than CH and that the H atoms in the CH2 of trans-structure EDA more easily react with CF.

The Modification of Butadiene-Acrylonitrile Rubber with Vinylcyclohexyl Ketone

2002 ◽  
Vol 75 (4) ◽  
pp. 683-690
Author(s):  
Niyazi Şahidoğlu Resulov ◽  
Bekir Sari ◽  
Muzaffer Talu
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Mechanical Tests ◽  
Polymerization Process ◽  
Adhesive Properties ◽  
Initial Concentration ◽  
Good Adhesive ◽  
The Media ◽  
Trans Structure

Abstract Butadiene-acrylonitrile-vinylcyclohexyl ketone (BD-AN-VCHK) terpolymer was synthesized by radical polymerization. The structure of the synthesized terpolymer was elucidated by IR spectroscopy and physical and mechanical tests. BD-AN-VCHK terpolymer was stable at lower temperatures and exhibited good adhesive properties. It was also observed that the yield of terpolymer was dependent upon the initial concentration of VCHK and pH of the media. The percentage of conversion increased by increasing the initial concentration of VCHK. With addition of 10.8% VCHK to the BD-AN mixture, the glass transition temperature (Tg) value of the polymers decreased from −40 °C to −57 °C. However further increase of VCHK ratio (20.4%) resulted in the formation of the polymers with Tg value of −48 °C. It was shown that this was due to the fact that VCHK, entering the structure during polymerization process, converted the trans structure of butadiene sequences into the cis form.

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