Technique of Organic Chemistry. Volume VII. Organic Solvents. Physical Properties and Methods of Purification.

1955 ◽  
Vol 77 (22) ◽  
pp. 6087-6087
Author(s):  
Oliver Grummitt
Keyword(s):  
Organic Chemistry ◽  
Physical Properties ◽  
Organic Solvents

Modern Transparent Papers: Materials, Degradation, and the Effects of Some Conservation Treatments

1992 ◽  
Vol 267 ◽  
Author(s):  
Dianne Van Der Reyden ◽  
Christa Hofmann ◽  
Mary Baker ◽  
Marion Mecklenburg
Keyword(s):  
Physical Properties ◽  
Organic Solvents ◽  
Materials Characterization ◽  
Research Projects ◽  
Specific Chemical ◽  
Effects Of Aging ◽  
Composition Properties

ABSTRACTModern transparent papers, also known as tracing papers, require specific chemical and physical properties, such as translucency, smoothness, and whiteness, which are produced by specially formulated compositions and manufacturing procedures. Ironically, these special formulations may in some ways render such papers susceptible to problems from damage and degradation, while also making them particularly reactive to moisture and solvents that must be used in conservation treatments to correct these problems. In order to evaluate the effects of water and organic solvents on such papers, four research projects were designed to consider the variables of paper composition, properties, type of solvent, technique of application of solvent, and flattening. This paper summarizes findings on materials characterization, degradative effects of aging, and some effects of solvents used on transparent papers for stain reduction, humidification, and flattening.

scholarly journals Ten Essential Delocalization Learning Outcomes: How Well Are They Achieved?

2020 ◽  
Author(s):  
Myriam S. Carle ◽  
Romeo Junior El Issa ◽  
Nicolas Pilote ◽  
Alison Flynn
Keyword(s):  
Organic Chemistry ◽  
Physical Properties ◽  
Learning Outcomes ◽  
Causal Reasoning ◽  
Scientific Reasoning ◽  
Chemical Reactivity ◽  
Student Reasoning ◽  
Resonance Structures ◽  
Research And Practice ◽  
Resonance Hybrid

<p>Delocalization (resonance) is a concept in organic chemistry that influences the chemical reactivity, structure, and physical properties of molecules. However, the concept has proven challenging for students and the related learning outcomes had previously been only vaguely defined. We recently defined ten essential learning outcomes about delocalization that a student should be able to demonstrate by the end of a two-course organic chemistry sequence. The goal of the present study was to investigate to what extent the ten LOs were achieved by students, as well as the connections between the LOs. We analyzed three exam questions related to seven of the ten LOs for the degree of achievement, common errors, and scientific reasoning. We found that students sometimes struggled to identify when delocalization could occur, that some of the LOs built on one another, and that students were more successful in drawing resonance structures when explicitly asked, but less successful when the requirement was implicit or embedded within a mechanism. Our analysis of student reasoning showed that the dominant modes of reasoning were aligned with the related expectations and explanations in the course. When asked to justify the contribution of resonance structures to the resonance hybrid, most answers used a descriptive mode of reasoning; when asked to explain why a given proton was more acidic than another, most answers contained relational and linear causal reasoning. Implications for research and practice are discussed.</p>

scholarly journals Efficient and Sustainable Synthesis of a Potent and Selective 5-HT7 Receptor Antagonist Using a Mechanochemical Approach

2020 ◽  
Author(s):  
Vittorio Canale ◽  
Valeria Frisi ◽  
Xavier Bantreil ◽  
Frédéric Lamaty ◽  
Paweł Zajdel
Keyword(s):  
Organic Chemistry ◽  
Receptor Antagonist ◽  
Ball Milling ◽  
Organic Solvents ◽  
Column Chromatography ◽  
Alkylating Agent ◽  
Synthetic Organic Chemistry ◽  
Final Compound ◽  
Excellent Tool

<div> <p>Recently, ball milling has become an excellent tool in synthetic organic chemistry as it offers several advantages over classical batch synthesis. Here, an efficient and sustainable mechanochemical procedure was developed to obtain <b>PZ-1361</b>, a potent and selective 5-HT<sub>7</sub> receptor antagonist, with significant antidepressant properties in rodents. The elaborated protocol limited the use of organic solvents, reduced the excess of the alkylating agent, and enabled to avoid column chromatography purification of intermediates and the final compound.</p> </div>

Strong Hydrogen Bonds Are Not Shielded in Ionic Liquids

2019 ◽  
Author(s):  
Teresa Naranjo ◽  
Rubén Álvarez-Asencio ◽  
Patricia Pedraz ◽  
Belén Nieto-Ortega ◽  
Enrique Burzurí ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Melting Point ◽  
Hydrogen Bonds ◽  
Physical Properties ◽  
Organic Solvents ◽  
Electrostatic Interactions ◽  
Room Temperature ◽  
Noncovalent Interactions ◽  
Binding Constants ◽  
Information Storage

Hydrogen bonds are arguably the most important of noncovalent interactions. The physical properties of water and the information storage in DNA depend on H-bonding, for instance. To this day, the balance between the Coulombic and covalent contributions to H-bonds is still under debate. Here, we show that H-bonded host-guest systems associate in ionic liquids, pure salts with melting point below room temperature, in which dipole-dipole electrostatic interactions should be negligible in comparison with dipole-charge interactions. Binding constants (<i>K</i><sub>a</sub>) obtained from titrations of four H-bonded host-guest systems in two organic solvents and two ionic liquids yield smaller yet comparable <i>K</i><sub>a</sub>values in ionic liquids than in organic solvents. We also detect the association event using force spectroscopy. Our results indicate that strong H-bonds are only moderately affected by surroundings composed entirely of charges, suggesting that the balance of Coulombic to covalent forces is not tipped towards the former.

Strong Hydrogen Bonds Are Not Shielded in Ionic Liquids

2019 ◽  
Author(s):  
Teresa Naranjo ◽  
Rubén Álvarez-Asencio ◽  
Patricia Pedraz ◽  
Belén Nieto-Ortega ◽  
Enrique Burzurí ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Melting Point ◽  
Hydrogen Bonds ◽  
Physical Properties ◽  
Organic Solvents ◽  
Electrostatic Interactions ◽  
Room Temperature ◽  
Noncovalent Interactions ◽  
Binding Constants ◽  
Information Storage

Hydrogen bonds are arguably the most important of noncovalent interactions. The physical properties of water and the information storage in DNA depend on H-bonding, for instance. To this day, the balance between the Coulombic and covalent contributions to H-bonds is still under debate. Here, we show that H-bonded host-guest systems associate in ionic liquids, pure salts with melting point below room temperature, in which dipole-dipole electrostatic interactions should be negligible in comparison with dipole-charge interactions. Binding constants (<i>K</i><sub>a</sub>) obtained from titrations of four H-bonded host-guest systems in two organic solvents and two ionic liquids yield smaller yet comparable <i>K</i><sub>a</sub>values in ionic liquids than in organic solvents. We also detect the association event using force spectroscopy. Our results indicate that strong H-bonds are only moderately affected by surroundings composed entirely of charges, suggesting that the balance of Coulombic to covalent forces is not tipped towards the former.

Ionic Liquid Promoted Eco-friendly and Efficient Synthesis of Six-membered Npolyheterocycles

2018 ◽  
Vol 15 (8) ◽  
pp. 1124-1146 ◽  
Author(s):  
Navjeet Kaur
Keyword(s):  
Organic Chemistry ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Organic Solvents ◽  
Review Article ◽  
Environmentally Benign ◽  
Wide Range ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Reaction Media

Background: The synthesis of N-polyheterocycles by environmentally benign method is highly attractive but challenging proposition. New strategies have been developed for the preparation of polycyclic heterocycles in the last decades. In this review article, the synthesis of nitrogen containing six-membered polycyclic heterocyclic compounds is presented with the application of ionic liquids. This contribution focuses on the literature related to the total synthesis of six-membered N-polyheterocycles. Objective: Ionic liquids not only acted as environmentally benign reaction media but also as catalysts which afforded the very promising replacements of traditional molecular solvents in organic chemistry due to their stability, non-flammability, non-volatility and ease of recyclability. Ionic liquids are utilized in metal catalyzed reactions in place of organic solvents in the last years. It has attracted considerable attention in recent years. Ionic liquids acted as alternatives of organic solvents and these ILs are environment friendly. Conclusion: In the area of green chemistry ionic liquid assisted synthesis is a very promising technique which afforded a flexible platform for the formation of heterocycles. The influence of ILs on the development of efficient and new synthetic protocols over the last decade for the construction of N-polyheterocycles is featured in this review article. These synthetic strategies will continue to attract more attention and will find a wide range of applications in organic synthesis. In conclusion, ionic liquids assisted syntheses have become an efficient and powerful tool in organic chemistry quickly.

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