Observation of Water Dangling OH Bonds Around Dissolved Nonpolar Groups
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Improved Procedure for the Reductive Acetylation of Acyclic Esters and a New Synthesis of Ethers
J. Org. Chem. 2000, 65, 191-198 191 Improved Procedure for the Reductive Acetylation of Acyclic Esters and a New Synthesis of Ethers David J. Kopecky and Scott D. Rychnovsky* Department of Chemistry, University of California, Irvine, California 92717-2025 Received September 14, 1999 An optimized protocol for the DIBALH reductive acetylation of acyclic esters and diesters is described. This reductive acetylation procedure allows a wide variety of esters to be converted into the corresponding R-acetoxy ethers in good to excellent yields. It was found that, under mild acidic conditions, many R-acetoxy ethers can be further reduced to the corresponding ethers. This net two-step ester deoxygenation is an attractive alternative to the classical Williamson synthesis for certain ethers. Introduction The reduction and in situ acetylation of esters was developed in our laboratory several years ago to provide access to unusual cyclic acetal structures.1 The general strategy involved trapping of the aluminum hemiacetal intermediate found in the reduction of an ester to an aldehyde by diisobutylaluminum hydride (DIBALH). Other groups had previously trapped the same type of intermediate with a trimethylsilyl group.2 After some exploration, we found that acetic anhydride, DMAP, and pyridine led to efficient trapping to give R-acetoxy ethers 1 Figure 1. Original DIBALH reductive acetylation conditions from the cyclic esters we had been studying. We were for lactones and some acyclic esters. surprised to find that the same conditions gave satisfac- R tory yields of the -acetoxy ethers from acyclic esters. a 12 h period, an R-acetoxy ether of the general structure The R-acetoxy ethers can be activated with a variety of 3 was isolated. -
Microscopic Dynamics of Charge Separation at the Aqueous Electrochemical Interface
Microscopic dynamics of charge separation at the aqueous electrochemical interface John A. Kattirtzia,b, David T. Limmerc,d,e,1, and Adam P. Willarda,1 aDepartment of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02138; bCollege of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China; cDepartment of Chemistry, University of California, Berkeley, CA 94609; dKavili Energy NanoScience Institute, University of California, Berkeley, CA 94609; and eMaterial Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94609 Edited by Michael L. Klein, Temple University, Philadelphia, PA, and approved June 6, 2017 (received for review March 7, 2017) We have used molecular simulation and methods of importance the process of aqueous ion association (forward reaction above) sampling to study the thermodynamics and kinetics of ionic or dissociation (reverse reaction above) is deceptively simple. charge separation at a liquid water–metal interface. We have con- The expression omits the cooperative role of solvent, which sidered this process using canonical examples of two different must restructure to accommodate transitions between the asso- classes of ions: a simple alkali–halide pair, Na+I−, or classical ions, ciated and dissociated states (2, 11). This restructuring, which + − and the products of water autoionization, H3O OH , or water is driven by thermal fluctuations, is both collective (extending ions. We find that for both ion classes, the microscopic mecha- beyond the first solvation shell) and fleeting (12–14). These nism of charge separation, including water’s collective role in the microscopic processes are difficult to probe experimentally (15), process, is conserved between the bulk liquid and the electrode so atomistic simulation has played an important role in reveal- interface. -
Catalytic Effect of Ultrananocrystalline Fe3o4 on Algal Bio-Crude Production Via HTL Process
Electronic Supplementary Material (ESI) for Nanoscale. This journal is © The Royal Society of Chemistry 2015 Catalytic Effect of Ultrananocrystalline Fe3O4 on Algal Bio-Crude Production via HTL Process Arnulfo Rojas-Péreza, Daysi Diaz-Diestraa,b, Cecilia B. Frias-Floresa, Juan Beltran-Huaraca,b, K. C. Dasc, Brad R. Weinera,b, Gerardo Morella,b and Liz M. Díaz-Vázquez*a Table 1-S: Profile of volatile and semivolatile compounds of the bio-crudes obtained from raw Ulva fasciata in absence of UNCFO (only compounds with quality identification factor higher that 70 were considered through NIST library) Library/ID Area Benzenepropanoic acid 0.1005 1H-Pyrrole 0.0114 Anthracene 0.0409 2,3,4-Trimethylpyrrole 0.0231 2,5-di-tert-Butyl-1,4-benzoquinone 0.0565 1H-Pyrrole 0.0493 Methylhydroquinon 0.1455 Pyridine 0.084 Acetophenone 0.0671 2-Pyridinamine, 4,6-dimethyl- 0.0094 Acetamide 0.08 2-Acetonylcyclopentanone 0.0097 1H-Indole, 2,6-dimethyl- 0.2334 Phenol 0.0503 1,2-Benzenediol 0.1657 Benzoic acid 0.09 Butylated Hydroxytoluene 0.2888 Benzenamine 0.0154 2-Isopropyl-10-methylphenanthrene 0.1123 2-Cyclopenten-1-one 0.147 5-Chloro-3-phenyl-1H-indazole 0.0976 2,4-Heptadiene 0.1024 1-Isopropyl-1H-indole 0.1426 Nonanoic acid 0.0385 Anthracene 0.067 7-Methylindan-1-one 0.0168 2,5-Diphenyl-2,4-hexadiene 0.0685 3-Methylcatechol 0.1156 2,3,7-Trimethylindole 0.2276 Acetophenone 0.1829 2-Methyl-5-(hexyn-1-yl)pyridine 0.0527 1H-Indole 0.1785 1-Nonadecene 0.2075 Acetamide, 0.1709 Heptadecanoic acid 0.2635 2,4-Diamino-N,N,5-trimethyl-6- 0.2219 9-Octadecenoic acid -
Solvent Effects on the Thermodynamic Functions of Dissociation of Anilines and Phenols
University of Wollongong Research Online University of Wollongong Thesis Collection 1954-2016 University of Wollongong Thesis Collections 1982 Solvent effects on the thermodynamic functions of dissociation of anilines and phenols Barkat A. Khawaja University of Wollongong Follow this and additional works at: https://ro.uow.edu.au/theses University of Wollongong Copyright Warning You may print or download ONE copy of this document for the purpose of your own research or study. The University does not authorise you to copy, communicate or otherwise make available electronically to any other person any copyright material contained on this site. You are reminded of the following: This work is copyright. Apart from any use permitted under the Copyright Act 1968, no part of this work may be reproduced by any process, nor may any other exclusive right be exercised, without the permission of the author. Copyright owners are entitled to take legal action against persons who infringe their copyright. A reproduction of material that is protected by copyright may be a copyright infringement. A court may impose penalties and award damages in relation to offences and infringements relating to copyright material. Higher penalties may apply, and higher damages may be awarded, for offences and infringements involving the conversion of material into digital or electronic form. Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong. Recommended Citation Khawaja, Barkat A., Solvent effects on the thermodynamic functions of dissociation of anilines and phenols, Master of Science thesis, Department of Chemistry, University of Wollongong, 1982. -
Hydrated Sulfate Clusters SO4^2
Article Cite This: J. Phys. Chem. B 2019, 123, 4065−4069 pubs.acs.org/JPCB 2− n − Hydrated Sulfate Clusters SO4 (H2O)n ( =1 40): Charge Distribution Through Solvation Shells and Stabilization Maksim Kulichenko,† Nikita Fedik,† Konstantin V. Bozhenko,‡,§ and Alexander I. Boldyrev*,† † Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, Utah 84322-0300, United States ‡ Department of Physical and Colloid Chemistry, Peoples’ Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya St, Moscow 117198, Russian Federation § Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka 142432, Moscow Region, Russian Federation *S Supporting Information 2− ABSTRACT: Investigations of inorganic anion SO4 interactions with water are crucial 2− for understanding the chemistry of its aqueous solutions. It is known that the isolated SO4 dianion is unstable, and three H2O molecules are required for its stabilization. In the 2− current work, we report our computational study of hydrated sulfate clusters SO4 (H2O)n (n =1−40) in order to understand the nature of stabilization of this important anion by fi 2− water molecules. We showed that the most signi cant charge transfer from dianion SO4 ≤ 2− to H2O takes place at a number of H2O molecules n 7. The SO4 directly donates its charge only to the first solvation shell and surprisingly, a small amount of electron density of 0.15|e| is enough to be transferred in order to stabilize the dianion. Upon further addition of ff ≤ H2O molecules, we found that the cage e ect played an essential role at n 12, where the fi 2− | | rst solvation shell closes. -
Solvation Structure of Ions in Water
International Journal of Thermophysics, Vol. 28, No. 2, April 2007 (© 2007) DOI: 10.1007/s10765-007-0154-6 Solvation Structure of Ions in Water Raymond D. Mountain1 Molecular dynamics simulations of ions in water are reported for solutions of varying solute concentration at ambient conditions for six cations and four anions in 10 solutes. The solutes were selected to show trends in properties as the size and charge density of the ions change. The emphasis is on how the structure of water is modified by the presence of the ions and how many water molecules are present in the first solvation shell of the ions. KEY WORDS: anion; cation; molecular dynamics; potential functions; solva- tion; water. 1. INTRODUCTION The behavior of aqueous solutions of salts is a topic of continuing interest [1–3]. In this note we examine how the structure of water,as reflected in the oxy- gen–oxygen pair function, is modified as the concentration of ions increases. The method of generating the pair functions is molecular dynamics using the SPC/E model for water [4] and various models for ion–water interactions taken from the literature. The solutes are LiCl, NaCl, KCl, RbCl, NaF, CaCl2, CaSO4,Na2SO4, NaNO3, and guanidinium chloride (GdmCl) [C(NH2)3Cl]. This work is an extension of earlier work [5] to a larger set of ions. The water molecules and ions interact through site–site pair interac- tions consisting of Lennard–Jones potentials and Coulomb interactions so that the interaction between a pair of sites labeled i, j and separated by an interatomic distance r is 12 6 φij (r) = 4ij (σij /r) − (σij /r) + qiqj /r (1) where qi is the charge on site i. -
Correlation Between Solubility and the Number of Water Molecules in the First Solvation Shell
Pure &App/. Chem., Vol. 70, No. 10, pp. 1895-1904, 1998. Printed in Great Britain. 0 1998 IUPAC Solubility of gases in water: Correlation between solubility and the number of water molecules in the first solvation shell Pirketta Scharlin,a Rubin Battino,b Estanislao Silla,c Iiiaki Tuii6nc and Juan Luis Pascual-Ahuirc a Department of Chemistry, University of Turku, FIN-20014 Turku, Finland Department of Chemistry, Wright State University, Dayton, Ohio 45435, USA Departamento de Quimica Fisica, Universidad de Valbncia, 46100 Burjassot, Valbncia, Spain Abstract: Using a new version of a program called GEPOL, a consistent set of values for areas of three different kinds of surfaces for 53 gaseous solutes was computed by Silla et al. These surface areas, together with the volumes of space enclosed by the surfaces, are reported in the present paper. The three surfaces are the van der Waals Surface (WS), the Solvent Accessible Surface (SAS) and the Solvent-Excluding Surface (SES). Values for the number of water molecules (N) in the first solvation shell are estimated by a simple surface area approach from the SAS data. Values of N, as well as literature data on solubilities of gases in water, are used to study various semi-empirical correlations between thermodynamic changes on solution and the number of water molecules in the first solvation shell. Dilute aqueous solutions of gases have been of continuous experimental and theoretical interest. Reliable solubility data exist for a large variety of gases in water. '-18 Experimental data have been important for validating the results of theoretical calculations, computer simulations, and various practical applications. -
The Ionization Constant of Water Over Wide Ranges of Temperature and Density
The Ionization Constant of Water over Wide Ranges of Temperature and Density Andrei V. Bandura Department of Quantum Chemistry, St. Petersburg State University, 26 University Prospect, Petrodvoretz, St. Petersburg 198504, Russia Serguei N. Lvova… The Energy Institute and Department of Energy & Geo-Environmental Engineering, The Pennsylvania State University, 207 Hosler Building, University Park, Pennsylvania 16802 ͑Received 26 April 2004; revised manuscript received 1 March 2005; accepted 5 April 2005; published online 8 December 2005͒ A semitheoretical approach for the ionization constant of water, KW , is used to fit the available experimental data over wide ranges of density and temperature. Statistical ther- modynamics is employed to formulate a number of contributions to the standard state chemical potential of the ionic hydration process. A sorption model is developed for calculating the inner-shell term, which accounts for the ion–water interactions in the immediate ion vicinity. A new analytical expression is derived using the Bragg–Williams approximation that reproduces the dependence of a mean ion solvation number on the solvent chemical potential. The proposed model was found to be correct at the zero- density limit. The final formulation has a simple analytical form, includes seven adjust- able parameters, and provides good fitting of the collected KW data, within experimental uncertainties, for a temperature range of 0 – 800 °C and densities of 0 – 1.2 g cmϪ3.©2006 American Institute of Physics. ͓DOI: 10.1063/1.1928231͔ Key words: Bragg–Williams approximation; high temperatures and low densities; ionization constant of water; statistical thermodynamics solvation model. Contents 3. References on the experimentally obtained KW data used for estimating the empirical parameters Nomenclature............................. -
Structure of Solvated Metal Ions
Structure of solvated metal ions Solution and crystal structure of Ga3+, In3+, Sc3+, Y3+, La3+ and Ca2+ ions with water and non-aqueous oxygen donor solvents Patric Lindqvist-Reis Doctoral Thesis Department of Chemistry Stockholm 2000 Patric Lindqvist-Reis Department of Chemistry Inorganic Chemistry Royal Institute of Technology S-100 44 Stockholm Sweden Printed by Kista Snabbtryck AB ON THE COVER: 3+ Sc(H2O)8 ions in the crystal structure of [Sc(H2O)8](CF3SO3)3 ROYAL ISBN 91-7170-569-4 INSTITUTE OF ISSN 0348-825X TECHNOLOGY TRITA-OOK-1060 STRUCTURE OF SOLVATED METAL IONS Solution and crystal structure of Ga3+, In3+, Sc3+, Y3+, La3+ and Ca2+ ions with water and non-aqueous oxygen donor solvents Patric Lindqvist-Reis Akademisk avhandling som med tillstånd av Kungliga Tekniska Högskolan i Stockholm framlägges till offentlig granskning för avläggande av filosofie doktorsexamen i oorganisk kemi, onsdagen den 14 juni, kl. 10.00 i kollegiesalen, administrationsbyggnaden, KTH, Vallhallavägen 79, Stockholm Avhandlingen försvaras på engelska. Abstract The structure of the solvated group 3 ions scandium(III), yttrium(III) and lanthanum(III), has been determined in aqueous solution and in some oxygen donor solvents, and compared with the hydrated group 13 ions gallium(III) and indium(III). A combination of X-ray absorption fine structure (XAFS), large angle X-ray scattering (LAXS), crystallography and vibration spectroscopy has been used for the structure studies of the hydrated ions and their dimethylsulfoxide and N,N´-dimethylpropylene urea solvates in solution and in the solid state. For the hexahydrated gallium(III) and indium(III) ions in solution, the metal-oxygen distances were found to be 1.959(6) Å and 2.131(7) Å to the first hydration shell, and 4.05(1) and 4.13(1) Å, respectively, to fairly well-defined second hydration shells containing about twelve water molecules. -