Effects of molecular structure parameters on ring-opening reaction of benzoxazines

2001 ◽  
Vol 44 (5) ◽  
pp. 552-560 ◽  
Author(s):  
Xin Liu ◽  
Yi Gu
Keyword(s):  
Molecular Structure ◽  
Ring Opening ◽  
Structure Parameters ◽  
Ring Opening Reaction

Preparation, Characterization and Application of Siloxane Succinate Fatliquor

2011 ◽  
Vol 233-235 ◽  
pp. 292-297 ◽  
Author(s):  
Tao Tao Qiang ◽  
Xiang Luo ◽  
Long Fang Ren ◽  
Xue Chuan Wang ◽  
Bao Yuan He
Keyword(s):  
Molecular Structure ◽  
Mechanical Properties ◽  
Castor Oil ◽  
Ring Opening ◽  
Rapeseed Oil ◽  
Raw Materials ◽  
Decomposition Temperature ◽  
Thermal Decomposition Temperature ◽  
Dyeing Property ◽  
Ring Opening Reaction

The silicone succinate surfactant (PMPS) was synthesized by ring-opening reaction using polyether alcohol amine modified polysilosane (PAPS) with maleic anhydride (MA) as the raw materials, and p-toluenesulfonic acid (PTSA) was used as the catalyst. Sulfated castor oil and sulfated rapeseed oil were combinated with PMPS to prepare a new leather fatliqour (PMPSF) composed mainly of PMPS. The molecular structure of PMPS was characterized by FTIR spectra; the thermal properties of PMPS was characterized and analyzed by TGA. PMPSF was used in sheepskin wet blue leather and compared with oxidative sulfited vegetable oils (L-3) and RF-1 fatliquor; the waterproof and mechanical properties of the leather were measured. The results show that the thermal decomposition temperature of PMPS is 192.8°C. Fatliquor PMPSF provids a good level-dyeing property, the leather oiled by it has good flexibility and fullness, the waterproofness and mechanical properties of leather are also good. Moreover, compared with the leather fatliquored by L-3, the thickening rate of leather oiled by PMPSF reaches 13.7%.

scholarly journals Visible-light Mediated Ring Opening Reaction of Alkylidenecyclopropanes for the Generation of Homopropargyl Radical

2021 ◽  
Author(s):  
Xiao-Yu Zhang ◽  
Chao Ning ◽  
Ben Mao ◽  
Yin Wei ◽  
Min Shi
Keyword(s):  
Molecular Structure ◽  
Visible Light ◽  
Ring Opening ◽  
Mechanistic Studies ◽  
Radical Process ◽  
Ring Opening Reaction ◽  
Long Time ◽  
Radical Clock

Classical cyclopropylcarbinyl radical clock reactions have been widely applied to conduct the mechanistic studies on probing radical process for a long time; however, alkylidenecyclopropanes, which have a similar molecular structure...

scholarly journals Ein monocyclisches Phosphoran mit axial gebundenem Wasserstoff: Darstellung und Molekülstruktur / A Monocyclic Phosphorane with Hydrogen in Axial Position: Preparation and Molecular Structure

1985 ◽  
Vol 40 (11) ◽  
pp. 1593-1596 ◽  
Author(s):  
Gerd-Volker Röschenthaler ◽  
Rainer Bohlen ◽  
Dietmar Schomburg
Keyword(s):  
Molecular Structure ◽  
Dimethyl Sulfoxide ◽  
Structure Analysis ◽  
Ring Opening ◽  
Axial Position ◽  
X Ray ◽  
Ring Opening Reaction

Chlorodiphenylphosphane and triethylammonium perfluoropinacolate yield the monocyclic hydrophosphorane 3. The X-ray structure analysis reveals that hydrogen is bonded in the axial position of a trigonal bipyramide. With dimethyl sulfoxide 3 undergoes a ring opening reaction to give phosphinate 5.

On the Conrotatory Ring Opening of 3-Carbomethoxycyclobutene Vis-À-Vis 3-Carbomethoxy-1,2-Benzocyclobutene and the Predominant Inward Opening of 3-Dimethylaminocarbonyl-1,2-Benzocyclobutene

2018 ◽  
Author(s):  
Veejendra Yadav ◽  
Dasari L V K Prasad ◽  
Arpita Yadav ◽  
Maddali L N Rao
Keyword(s):  
Transition State ◽  
Ring Opening ◽  
Electron Process ◽  
Ring Opening Reaction ◽  
Stable Species ◽  
Electron Event

<p>The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by p<sub>C1C2</sub>→s*<sub>C3C4</sub> and s<sub>C3C4</sub>→p*<sub>CO</sub> interactions in the transition state in a 4-electron process as opposed to only s<sub>C3C4</sub>→p*<sub>CO</sub> interaction in an apparently 8-electron event in 3-carbomethoxy-1,2-benzocyclobutene. The ring opening of 3-carbomethoxy-1,2-benzocyclobutene is sufficiently endothermic. We therefore argue that the reverse ring closing reaction is faster than the forward ring opening reaction and, thus, it establishes an equilibrium between the two and subsequently allows formation of the more stable species <i>via</i> outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.</p>

scholarly journals Expanding Monomers as Anti-Shrinkage Additives

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 806
Author(s):  
Philipp Marx ◽  
Frank Wiesbrock
Keyword(s):  
Ring Opening ◽  
Covalent Bond ◽  
Volumetric Shrinkage ◽  
Structure Property ◽  
Atomic Packing ◽  
Materials Properties ◽  
Volumetric Expansion ◽  
Structure Property Relationships ◽  
Ring Opening Reaction ◽  
Measuring Techniques

Commonly, volumetric shrinkage occurs during polymerizations due to the shortening of the equilibrium Van der Waals distance of two molecules to the length of a (significantly shorter) covalent bond. This volumetric shrinkage can have severe influence on the materials’ properties. One strategy to overcome this volumetric shrinkage is the use of expanding monomers that show volumetric expansion during polymerization reactions. Such monomers exhibit cyclic or even oligocyclic structural motifs with a correspondingly dense atomic packing. During the ring-opening reaction of such monomers, linear structures with atomic packing of lower density are formed, which results in volumetric expansion or at least reduced volumetric shrinkage. This review provides a concise overview of expanding monomers with a focus on the elucidation of structure-property relationships. Preceded by a brief introduction of measuring techniques for the quantification of volumetric changes, the most prominent classes of expanding monomers will be presented and discussed, namely cycloalkanes and cycloalkenes, oxacycles, benzoxazines, as well as thiocyclic compounds. Spiroorthoesters, spiroorthocarbonates, cyclic carbonates, and benzoxazines are particularly highlighted.

Design and synthesis of 1,8-Naphthalimide Functionalized Benzothiadiazoles

2021 ◽  
Author(s):  
Rajneesh Misra ◽  
Yogjivan Rout
Keyword(s):  
Ring Opening ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Design And Synthesis ◽  
Cross Coupling Reaction ◽  
Ring Opening Reaction

A series of multi acceptor based push-pull derivatives BTD2–BTD5 were designed and synthesized via Pd-catalyzed Sonogashira cross-coupling reaction followed by [2+2] cycloaddition–electrocyclic ring-opening reaction in which benzothiadiazole (BTD, A1), naphthalimide...

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