Isolation and Purification of Organic Compounds Extraction (Expt
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Acidity, Basicity, and Pka 8 Connections
Acidity, basicity, and pKa 8 Connections Building on: Arriving at: Looking forward to: • Conjugation and molecular stability • Why some molecules are acidic and • Acid and base catalysis in carbonyl ch7 others basic reactions ch12 & ch14 • Curly arrows represent delocalization • Why some acids are strong and others • The role of catalysts in organic and mechanisms ch5 weak mechanisms ch13 • How orbitals overlap to form • Why some bases are strong and others • Making reactions selective using conjugated systems ch4 weak acids and bases ch24 • Estimating acidity and basicity using pH and pKa • Structure and equilibria in proton- transfer reactions • Which protons in more complex molecules are more acidic • Which lone pairs in more complex molecules are more basic • Quantitative acid/base ideas affecting reactions and solubility • Effects of quantitative acid/base ideas on medicine design Note from the authors to all readers This chapter contains physical data and mathematical material that some readers may find daunting. Organic chemistry students come from many different backgrounds since organic chemistry occu- pies a middle ground between the physical and the biological sciences. We hope that those from a more physical background will enjoy the material as it is. If you are one of those, you should work your way through the entire chapter. If you come from a more biological background, especially if you have done little maths at school, you may lose the essence of the chapter in a struggle to under- stand the equations. We have therefore picked out the more mathematical parts in boxes and you should abandon these parts if you find them too alien. -
Protonation of Citraconic and Glutaconic Acid In
M. Jankulovska-Petkovska, M. S. Jankulovska, V. Dimova, “Protonation of citraconic and glutaconic acid…”, Technologica Acta , vol. 12, no. 1, pp. 1–8, 2019. 1 PROTONATION OF CITRAC ONIC AND GLUTACONIC ACID IN PERCHLORIC ACID MEDIA ORIGINAL SCIENTIFIC PAPER Milena Jankulovska-Petkovska 1, Mirjana S. 2 3 Jankulovska *, Vesna Dimova DOI: 10.5281/zenodo.3267263 RECEIVED ACCEPTED 1 Ss Kliment Ohridski University, Faculty of Veterinary Medicine in Bitola, Macedonia 2019-01-22 2019-04-05 2 Ss. Cyril and Methodius University, Faculty of Agricultural Sciences and Food in Skopje, Macedonia 3 Ss Cyril and Methodius University, Faculty of Technology and Metallurgy in Skopje, Macedonia * [email protected] ABSTRACT: The protonation process of citraconic and glutaconic acid in perchloric acid media was followed us- ing the method of UV spectroscopy. The observed changes in the UV spectra of investigated acids confirmed that the protonation process in perchloric acid with concentration from 5 to 10 mol/dm 3 occurred. Glutaconic acid be- haved as weak organic base in perchloric acid media and existed in its monoprotonated form. On the other hand, citraconic acid existed in its protonated form and as protonated anhydride at higher perchloric acid concentra- tion. Using the absorbance data the thermodynamic dissociation constants were calculated applying the methods of Yates and McClelland, Bunnett and Olsen, and the “excess acidity” function method. The solvatation parame- ters m, m* and φφφ were evaluated, as well. In order to correct the medium effect the method of characteristic vector analysis was applied. The possible site where the protonation may take place was discussed using the partial atomic charge values determined according to AM1 and PM3 semiempirical methods. -
Laboratory Analysis of Organic Acids, 2018 Update: a Technical Standard of the American College of Medical Genetics and Genomics (ACMG)
© American College of Medical Genetics and Genomics ACMG TECHNICAL STANDARD Laboratory analysis of organic acids, 2018 update: a technical standard of the American College of Medical Genetics and Genomics (ACMG) Renata C. Gallagher MD, PhD1, Laura Pollard, PhD2, Anna I. Scott, PhD3,4, Suzette Huguenin, PhD5, Stephen Goodman, MD6, Qin Sun, PhD7; on behalf of the ACMG Biochemical Genetics Subcommittee of the Laboratory Quality Assurance Committee Disclaimer: This laboratory standard is designed primarily as an educational resource for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to this standard is voluntary and does not necessarily assure a successful medical outcome. This standard should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the clinical laboratory geneticist should apply his or her own professional judgment to the specific circumstances presented by the individual patient or specimen. Clinical laboratory geneticists are encouraged to document in the patient’s record the rationale for the use of a particular procedure or test, whether or not it is in conformance with this standard. They also are advised to take notice of the date any articular standard was adopted, and to consider other relevant medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures. Organic acid analysis detects accumulation of organic acids in urine guidance for laboratory practices in organic acid analysis, and other body fluids and is a crucial first-tier laboratory test for a interpretation, and reporting. -
Organic Acids and Bases
H O H C C C C O = C C H = H C O H C O H3C aspirin CHEMISTRY 2000 Topic #3: Organic Chemistry Fall 2020 Dr. Susan Findlay See Exercises in Topic 12 Measuring Strength of Acids When you hear the term “organic acid”, it usually refers to a carboxylic acid. Carboxylic acids are readily deprotonated by strong bases: .O. .O. -... H .. H C .. H + .O H C .. + O H C O .. H C O.- .. 3 .. 3 ... acid base conjugate base conjugate acid This reaction is favoured in the forward direction because the products are lower in energy than the reactants. In particular, the conjugate base (acetate; ) is much more stable than the original base (hydroxide, ). − 32 Therefore, acetate is a weaker base than hydroxide.− Therefore, acetic acid is a stronger acid than water. 2 Measuring Strength of Acids An acid’s strength depends on the stability of its conjugate base: The conjugate base of (a strong acid; = 7) is (a very weak base) − − The conjugate base of (a weak acid; = 14) is (a relatively strong base) − 2 The strength of an acid can therefore be said to be inversely related to the strength of its conjugate base (and vice versa). Why is more stable than ? − − 32 3 Measuring Strength of Acids- Consider the reaction below. Identify the acid, base, conjugate acid and conjugate base. Is this reaction product-favoured or reactant-favoured? The of is 5. The of is 14. 32 The of 2 is 0. + 3 .O. .O. H .. H H ..+ H C .. H + O C . -
The Effect of Organic Acids on Base Cation Leaching from the Forest ¯Oor Under Six North American Tree Species
European Journal of Soil Science, June 2001, 52, 205±214 The effect of organic acids on base cation leaching from the forest ¯oor under six North American tree species a,c b b b a F. A. DIJKSTRA ,C.GEIBE ,S.HOLMSTROÈ M ,U.S.LUNDSTROÈ M &N.VAN BREEMEN aLaboratory of Soil Science and Geology, PO Box 37, 6700 AA Wageningen, The Netherlands, bDepartment of Chemistry and Process Technology, Mid Sweden University, 85170 Sundsvall, Sweden, and cInstitute of Ecosystem Studies, Box AB, Route 44A, Millbrook, NY 12545, USA Summary Organic acidity and its degree of neutralization in the forest ¯oor can have large consequences for base cation leaching under different tree species. We investigated the effect of organic acids on base cation leaching from the forest ¯oor under six common North American tree species. Forest ¯oor samples were analysed for exchangeable cations and forest ¯oor solutions for cations, anions, simple organic acids and acidic properties. Citric and lactic acid were the most common of the acids under all species. Malonic acid was found mainly under Tsuga canadensis (hemlock) and Fagus grandifolia (beech). The organic acids were positively correlated with dissolved organic carbon and contributed signi®cantly to the organic acidity of the solution (up to 26%). Forest ¯oor solutions under Tsuga canadensis contained the most dissolved C and the most weak acidity among the six tree species. Under Tsuga canadensis we also found signi®cant amounts of strong acidity caused by deposition of sulphuric acid from the atmosphere and by strong organic acids. Base cation exchange was the most important mechanism by which acidity was neutralized. -
Extraction Methods and Their Influence on Yield When Extracting Thermo-Vacuum-Modified Chestnut Wood
Article Extraction Methods and Their Influence on Yield When Extracting Thermo-Vacuum-Modified Chestnut Wood Maurizio D’Auria 1 , Marisabel Mecca 1, Maria Roberta Bruno 2 and Luigi Todaro 2,* 1 Department of Science, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy; [email protected] (M.D.); [email protected] (M.M.) 2 School of Agricultural Forestry, Food, and Environmental Science, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy; [email protected] * Correspondence: [email protected]; Tel.: +39-3478782534 Abstract: Improvements in the yield and solubility of chestnut wood extractives, by using different extraction methods and molybdenum catalysts as support, have rarely been reported in literature. Many studies focus on the different parts of trees, except for the chemical characteristics of the remaining extractives achieved from thermally modified (THM) chestnut (Castanea sativa Mill) wood. This research seeks to better understand the effects of extraction techniques and catalysts on the yield and solubility of extractives. GC-MS analysis of the chloroform soluble and insoluble fractions was also used. Accelerated Solvent Extraction (ASE) 110 ◦C, Soxhlet, and autoclave extraction techniques were used to obtain extractives from untreated and thermally modified (THM) chestnut ◦ wood (170 C for 3 h). Ethanol/H2O, ethanol/toluene, and water were the solvents used for each technique. A polyoxometalate compound (H3PMo12O40) and MoO3 supported on silica were used as catalysts. The THM induced a change in the wood’s surface color (DE = 21.5) and an increase in mass loss (5.9%), while the equilibrium moisture content (EMC) was reduced by 17.4% compared to the control wood. -
Laboratory Manual
International Program UAM-Boston University Laboratory Manual Organic Chemistry I 2013-2014 Departamento de Química Orgánica Ernesto Brunet Romero Ana María Martín Castro Ramón Gómez Arrayás Laboratory Manual Table of Contents ............................................................................... 1 Introduction ............................................................................... 2 Prelab preparation ............................................................................... 2 Notebook ............................................................................. 3 Safety .............................................................................. 3 Laboratory Practices and Safety Rules ............................................................. 4 Accidents and injuries ........................................................................... 5 Fires ............................................................................. 5 Chemical Wastes ............................................................................. 6 Cleaning Responsibilities ............................................................................. 6 Lab cleanliness ............................................................................. 6 Laboratory Equipment ............................................................................. 7 Proper use of glassware ............................................................................. 8 Some techniques in lab experiments Heating, cooling and stirring ............................................................................ -
Role of Organic Acids in the Mechanisms of Biological Soil Disinfestation (BSD)
J Gen Plant Pathol (2006) 72:247–252 © The Phytopathological Society of Japan DOI 10.1007/s10327-006-0274-z and Springer-Verlag Tokyo 2006 FUNGAL DISEASES Short communication Noriaki Momma · Kazuhiro Yamamoto · Peter Simandi Masahiro Shishido Role of organic acids in the mechanisms of biological soil disinfestation (BSD) Received: May 18, 2005 / Accepted: December 9, 2005 Abstract Biological soil disinfestation (BSD), or reductive Although other chemical disinfestants for soil treatment soil disinfestation, achieved by amendment with organic such as chloropicrin, 1,3-dichloropropene, and methyl materials such as wheat bran followed by flooding and isothiocyanate, are still available, soil disinfestation using covering the soil surface, has been used to control some these chemicals has become widely recognized as measures soilborne diseases including Fusarium wilt and bacterial incompatible with sustainable agriculture. Therefore, it is wilt of tomato. During a BSD treatment, accumulation of imperative to find alternatives to chemical fumigation for acetic acid and/or butyric acid was detected with high- disinfesting soils. performance liquid chromatography. Survival of Fusarium A number of soilborne pathogens can be suppressed oxysporum f. sp. lycopersici or Ralstonia solanacearum was under anaerobic conditions (Cook and Baker 1983; Blok suppressed by these organic acids. Amendment of these et al. 2000). For example, populations of soilborne pa- organic acids into soil suppressed the survival of R. thogens in rice paddies can decrease during the flooding solanacearum at lower concentrations than the maximum period, and this suppression is often enhanced by the detected in BSD treatment, indicating that production of incorporation of readily decomposable organic matter such these organic acids is one of the mechanisms of control. -
Study of Superbase-Based Deep Eutectic Solvents As the Catalyst in the Chemical Fixation of CO2 Into Cyclic Carbonates Under Mild Conditions
materials Article Study of Superbase-Based Deep Eutectic Solvents as the Catalyst in the Chemical Fixation of CO2 into Cyclic Carbonates under Mild Conditions Sara García-Argüelles 1,2, Maria Luisa Ferrer 1,* , Marta Iglesias 1, Francisco Del Monte 1 and María Concepción Gutiérrez 1,* 1 Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, C/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain; [email protected] (S.G.-A.); [email protected] (M.I.); [email protected] (F.D.M.) 2 Departamento de Tecnología Química y Energética, Tecnologia Química y Ambiental y Tecnología Mecánica y Química Analítica, Universidad Rey Juan Carlos, 28933 Madrid, Spain * Correspondence: [email protected] (M.L.F.); [email protected] (M.C.G.); Tel.: +34-913349059 (M.L.F.); +34-913349056 (M.C.G.) Received: 8 June 2017; Accepted: 29 June 2017; Published: 7 July 2017 Abstract: Superbases have shown high performance as catalysts in the chemical fixation of CO2 to epoxides. The proposed reaction mechanism typically assumes the formation of a superbase, the CO2 adduct as the intermediate, most likely because of the well-known affinity between superbases and CO2, i.e., superbases have actually proven quite effective for CO2 absorption. In this latter use, concerns about the chemical stability upon successive absorption-desorption cycles also merits attention when using superbases as catalysts. In this work, 1H NMR spectroscopy was used to get further insights about (1) whether a superbase, the CO2 adduct, is formed as an intermediate and (2) the chemical stability of the catalyst after reaction. -
Method 3520C: Continuous Liquid-Liquid Extraction, Part of Test
METHOD 3520C CONTINUOUS LIQUID-LIQUID EXTRACTION 1.0 SCOPE AND APPLICATION 1.1 This method describes a procedure for isolating organic compounds from aqueous samples. The method also describes concentration techniques suitable for preparing the extract for the appropriate determinative steps described in Sec. 4.3 of Chapter Four. 1.2 This method is applicable to the isolation and concentration of water-insoluble and slightly soluble organics in preparation for a variety of chromatographic procedures. 1.3 Method 3520 is designed for extraction solvents with greater density than the sample. Continuous extraction devices are available for extraction solvents that are less dense than the sample. The analyst must demonstrate the effectiveness of any such automatic extraction device before employing it in sample extraction. 1.4 This method is restricted to use by or under the supervision of trained analysts. Each analyst must demonstrate the ability to generate acceptable results with this method. 2.0 SUMMARY OF METHOD 2.1 A measured volume of sample, usually 1 liter, is placed into a continuous liquid-liquid extractor, adjusted, if necessary, to a specific pH (see Table 1), and extracted with organic solvent for 18 - 24 hours. 2.2 The extract is dried, concentrated (if necessary), and, as necessary, exchanged into a solvent compatible with the cleanup or determinative method being employed (see Table 1 for appropriate exchange solvents). 3.0 INTERFERENCES 3.1 Refer to Method 3500. 3.2 The decomposition of some analytes has been demonstrated under basic extraction conditions required to separate analytes. Organochlorine pesticides may dechlorinate, phthalate esters may exchange, and phenols may react to form tannates. -
A Review of Supercritical Fluid Extraction
NAT'L INST. Of, 3'«™ 1 lY, 1?f, Reference NBS PubJi- AlllDb 33TA55 cations /' \ al/l * \ *"»e A U O* * NBS TECHNICAL NOTE 1070 U.S. DEPARTMENT OF COMMERCE / National Bureau of Standards 100 LI5753 No, 1070 1933 NATIONAL BUREAU OF STANDARDS The National Bureau of Standards' was established by an act of Congress on March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is per- formed by the National Measurement Laboratory, the National Engineering Laboratory, and the Institute for Computer Sciences and Technology. THE NATIONAL MEASUREMENT LABORATORY provides the national system ot physical and chemical and materials measurement; coordinates the system with measurement systems of other nations and furnishes essential services leading to accurate and uniform physical and chemical measurement throughout the Nation's scientific community, industry, and commerce; conducts materials research leading to improved methods of measurement, standards, and data on the properties of materials needed by industry, commerce, educational institutions, and Government; provides advisory and research services to other Government agencies; develops, -
Organic Functional Group Analysis
Experiment 1 1 Laboratory Experiments for GOB Chemistry ___________________________________________________________________________________________ I ORGANIC FUNCTIONAL GROUP ANALYSIS I. OBJECTIVES AND BACKGROUND This experiment will introduce you to some of the more common functional groups of organic chemistry. The functional group is that portion of the molecule that undergoes a structural change during a chemical reaction. The functional groups that will be studied in this experiment are carboxylic acid, amines aldehyde, ketone, alcohols and alkenes. You will learn chemical tests that will allow you to distinguish one functional group from another. You will use the chemical tests to identify the functionality of an unknown organic compound. In addition, you will use a water solubility test to determine whether your organic compound is of high or low formula weight. The chemical tests you will perform make up a sequence of experiments designed to determine the absence of or suggest the presence of particular functional groups. The complete sequence is shown in the flow diagram on page 8. This diagram can serve you in several ways: It is a summary of the procedure that you are to follow in classifying your unknown as one of the functional group types. It can order your thoughts as you read the discussion of each test, and help you to understand the significance of that test. It can enhance your appreciation for and enjoyment of this experiment. Your role is that of chemist and detective: you will employ this cleverly devised scheme to sleuth out the identity of your unknown's functionality. Experiment 1 2 Laboratory Experiments for GOB Chemistry ___________________________________________________________________________________________ Discussion of Chemical Tests 1.