...What is the main feature of the topic? The main feature of this topic is the Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization of N-acryloyl-L-phenylalanine (A-Phe-OH) where the carboxylics acid functional group is kept intact. Furthermore this is achieved without the use of a protecting group, such as methyl esters, as seen below. Figure 1: Preservation of Carboxylic Acid Moiety This article further examines the effect of chain transfer agents (CTA), solvents, temperature, and initiator molar ratio on the molecular weight distribution, and determines the optimal environment for direct polymerization. Why is this topic important? Carboxylic acid functional groups serve many purposes they confer to the polymer the ability to interact with a variety of substances. For example The use of amino based monomers with carboxylic acid moiety is the ability to adapt the polymers for various interactions with substances such as metal ions, non-ionic proton-accepting polymers, their derivatives, and cationic polyelectrolytes. As such these polymers can serve as a way of delivering drugs to targeted zones. Furthermore by polymerizing the monomers without the need for protecting groups serves a much more significant purpose on an industrial size. By avoiding the use of protecting groups one can avoid added steps in the industrial process, as such reducing the opportunities for errors to occur and avoiding additional costs associated with the protecting groups...
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...Holmgren et al. (2012) analyzes the energy balance of a commercial-scale methanol process featuring a biomass gasification system. Albeit trees and some microbes can capture CO₂ and converted it into more involute chemicals, humans have struggled to reproduce the process on an immensely colossal scale. Most chemical reactions involving CO₂ require sumptuous catalysts, high temperatures, or high pressures to react. The most mundane utilization of CO₂ as a chemical feedstock is in the formation of urea, which is found in around 91% of the world’s fertilisers (Breen , 2014). The kinetic models developed for the commixed reforming and synthesis of methanol (MeOH) by Nonam, et al. (2014). The experimental study of Conversion of CO2 into methanol...
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...0.162 0.160 yh2 = 0.6667 OR 0.762 OR 0.160 yetb = 0.3332 0.162 0.160 if you used incorrect R-value printed on exam if you switched DG and DH (since DH not labeled correctly) (4) In the absence of a selective catalyst, the synthesis of methanol can be accompanied by a side reaction in which coke (solid carbon) is formed (see below). If 1 mol CO and 2 mol H2 are fed to a reactor at 298 K and 0.5 bar, approximately how many moles of coke will form? CO(g) + 2H2(g) ( CH3OH(g) 2CO(g) ( CO2(g) + C(s) Compound ΔGf° ΔΗf° (kJ/mol) CO -137.2 -110.53 MeOH -162.2 -200.9 CO2 -394.4 -393.5 H2O -228.6 -241.9 Free energies of formation of pure elements are taken as the reference state, hence ΔGf°H2 = 0 and ΔGf°C(s) = 0...
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...Reproduced with permission from Energy for Sustainable Development Articles Synthetic fuel production by indirect coal liquefaction Eric D. Larson Princeton Environmental Institute, Princeton University Guyot Hall, Washington Road, Princeton, NJ 08544-1003, USA E-mail: elarson@princeton.edu Ren Tingjin Department of Thermal Engineering, Tsinghua University, 100084 Beijing, China This paper reports detailed process designs and cost assessments for production of clean liquid fuels (methanol and dimethyl ether) by indirect coal liquefaction (ICL). Gasification of coal produces a synthesis gas that can be converted to liquid fuel by synthesis over appropriate catalysts. Recycling of unconverted synthesis gas back to the synthesis reactor enables a larger fraction of the coal energy to be converted to liquid fuel. Passing synthesis gas once over the synthesis catalyst, with unconverted synthesis gas used to generate electricity in a gas turbine combined cycle, leads to less liquid fuel production, but provides for a significant second revenue stream from sale of electricity. Recently-developed liquid-phase synthesis reactors are especially attractive for ‘‘oncethrough’’ processing. Both ‘‘recycle’’ and ‘‘once-through’’ plant configurations are evaluated in this paper. Because synthesis catalysts are poisoned by sulfur, essentially all sulfur must be removed upstream. Upstream removal of CO2 from the synthesis gas is also desirable to maximize synthesis productivity, and it provides...
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...Pergamon PII: S0031-9422(96)00532-8 Phytochemistry, Vol. 44, No. 1, pp. 179-181, 1997 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0031-9422/97 $17.00 + 0.00 TWO COUMARINS FROM THE ROOT BARK OF CLAUSENA EXCAVATA SHIOW-CHYNHUANG,*PEI-LIN Wul" and TIAN-SHUNGWo't$ *Department of Pharmacy, Chia Nan College of Pharmacy and Science, Tainan Hsien, Taiwan, R.O.C. tDepartment of Chemistry, National Cheng Kung University,Talnan, Taiwan, R.O.C. (Received in revised form 1 July 1996) Key Word I n d e x - - C l a u s e n a claucavatin-B. excavata; Rutaceae; coumarin; flavonoid; claucavatin-A; Abstract--Two new pyrano-coumarins, claucavatin-A and -B, together with eight known coumarins and two known flavonoids were isolated and identified from the acetone extract of the root bark of Clausena excavata. Their structures were elucidated by the spectroscopic analyses. Copyright © 1996 Elsevier Science Ltd INTRODUCTION Clausena excavata has been used as a folk medicine in at 6 2.73 and a gem-dimethyl singlet at 6 1.62 indicated a 2'-2'-dimethyl-4-pyranone ring linearly attached to the coumarin ring. Unlike the two cis-vinyl protons found in 4, in 1 only one downfield singlet proton was seen (6 7.89). This suggests that there is a substituent attached to C-3. The remaining peaks disclosed pairs of 1,1-dimethylallyl groups at 8 1.46 and 1.47 (each 6H, s, each 2×CH3), 4.88 and 5.09 (each 1H, rid, each J = 10.4, 0.8 Hz), 4.92 and 5.10 (each 1H, dd,...
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...10/26/2010 STANDARDIZATION OF HERBAL PRODUCTS ZHARI ISMAIL & JAMSHED SIDDIQUI HEAD (R & D) CENTRE FOR HERBAL STANDARDISATION (CHEST) PUSAT PENGAJIAN SAINS FARMASI UNIV. SAINS MALAYSIA International Conference & Talkshow on Medicinal Plant 39th. Meeting of National Working Group on Indonesian Medicinal Plant. Jakarta, 19-20th October 2010 CONTENTS I. II. III. IV. V. VI. VII. VIII. Introduction: Overview of Standardization of plant extracts Meaning of Standardized Extracts Problems related to standardization of herbal products Common techniques used for standardization of herbal products Validation techniques for herbal products Standardization techniques for mixed herbal products Method for the determination of soluble sugars in plant extracts Conclusion Multiple subsectors for Herbs There are huge global opportunities for herbs based business Phytopharmaceuticals Modern drugs Drug leads Drug intermediates Low to High-End Products available for Herbs • Fast growing industry and require investment to become leader with short time to enter market High MAPs MAPs MAPs Herbal drugs Herbal drug preparation Herbal Med production Traditional medicines Complementary Alternate Medicines House hold remedies 26.6b 5.9b Herbs/Botanicals 5% Growth Rate Functional Foods Nutraceuticals 4.7b 25b Cosmeceuticals/ Cosmetics Insect repellants Insecticides Pesticides Fungicides Pharmaceutical Aids Gums Mucilages Edible dyes Sweeteners Essential Oils Flavours...
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...David O. Johnston David Lipscomb College I II The Methclnolysir of Acetal A chemical kinetics a n d g a r chromatography experiment Nashville, Tennessee The methanolysis of acetal and gas chromatography complement perfectly to provide a rare and interesting experiment for the physical chemistry student. The reaction of acetal with methanol is a consecutive reaction in which diethyl acetal (aretal) replaces its two ethoxy groups with methoxy groups forming methy1et)hylacetal first and dimethyl acetal in the second step. Investigating the reaction kinetics for this type of reaction mas almost impossible before the advent of gas chromatography (I). There are many advantages to using the methanolysis of acetal in this study: Sufficient data for a complete analysis can be collected within three hours. The reaction requires reagents which are readily available in high purity. The reactants, intermediate, and products are liquids at temperatures easily accessible for kinetic runs. The primary reactant, intermediate, and product are sepe rated rleanly on a typical gas chromatographic column. The peak heights are linear with concentration in the range studied (2). Analysis of the data affords an application of firshorder kin~ticsand the steady state hypothesis. The experiment presented herc is an adaptation of the detailed study of the reaction by Juvet and Chiu (2), who have shown it to be acid catalyzed and first order in diethyl acetal and methylethyl acetal. By decreasing...
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...THE HYPOGLYCEMIC EFFECT OF MAKOPA FRUIT EXTRACT (Syzygium malaccense) TO DIABETIC RATS Chapter I INTRODUCTION Background of the Study Malay Apple or commonly known as Makopa in the Philippines (Syzygium malaccense) is a very common plant in typical barrios. Most often, the Makopa fruit is swept after they fall in the ground during rainy seasons and it is easily spoiled. The waste material is biodegradable. However, the process of decomposition is slow and it gives an unpleasant view on the surrounding during this process. Hence, the wasted plant material adds up to a pile of garbage. Therefore, it is better to use the fruit of the Makopa to produce a product out of it in the form of anti-diabetic for every household. Most often, this tree is usually used as shade and the fruit of it is sometimes useless for when it falls to the ground, they are just swept and thrown away. Makopa trees when full grown, can serve as shelter to animals, like the gecko, or bugs and they may eat the fruits. To avoid wasting these fruit, it could be utilized as an anti-diabetic. Makopa should be used in a way that will benefit us. This observation gave the researchers the idea of using the Makopa as an effective treatment to diabetes which is very expensive nowadays. Statement of the Problem This study was conducted to produce sweetener out of the Makopa fruit. Specifically, it aimed to answer the following questions: 1. What are the active components of makopa extract? 2. What...
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...chromatography gave three main peaks on HPLC with mass spectra of 527, 272, and 661 m/z respectively, corresponding to sodium-monorhamnodecanoate, hydroxyhexadecanoic acid and an unknown compound, respectively. Sung Kwang Cho et al (2006) isoalted, three hundred and thirty two bacterial colonies from soil contaminated by an oil spill. All the bacteria were cultured in a liquid medium individually, and the surface tensions of the media were compared. The bacterium whose culture medium had the lowest surface tension was identified as Pseudomonas sp. G11. A biosurfactant was produced by cultivation of the Pseudomonas sp. G11 in the LB media. For extraction of the biosurfactant, two solvent systems were used (n-hexane and a 2:1 (v/v) mixture of chloroform/MeOH), and the results were compared. Various experimental conditions (solvent composition, flow rate, etc.) were tested to optimize the analysis of the biosurfactant by asymmetrical flow field-flow fractionation (AsFlFFF). The biosurfactant was successfully separated from the culture medium by AsFlFFF when pure water was used as the carrier. From the retention data, the hydrodynamic diameter (dH) and molecular weight (M) of the biosurfactant were determined by AsFlFFF. The molecular weight was determined by using pullulans as the calibration standards. S. George et al (2012) worked on to improve biosurfactant production economics by the utilization of potential low-cost materials. A novel P. aeruginosa strain that could use waste frying coconut...
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...Advanced Inorganic Chemistry I: Report Engineering the Optical Response of the Titanium-MIL-125 Metal-Organic Framework through Ligand Functionlization , 2013, 135 (30), pp 10942–10945 Advanced Inorganic Chemistry I: Report Engineering the Optical Response of the Titanium-MIL-125 Metal-Organic Framework through Ligand Functionlization , 2013, 135 (30), pp 10942–10945 Valeriya Chernikova PhD student KAUST November 2013 Valeriya Chernikova PhD student KAUST November 2013 Conductive metal-organic frameworks Conductive metal-organic frameworks Conductivity in metal-organic frameworks Metal–organic frameworks (MOFs), are a class of crystalline materials whose crystal structure is made up from metal-containing clusters connected by multidentate organic linkers1,2. MOFs are attracting considerable attention due to the possible rational design of crystal structures of coordination frameworks with versatile metal ions and organic ligands. In principle, MOFs topologies along with intermolecular distances between various building blocks can be controlled using the fundamentals of reticular chemistry. This offers a great potential for tailoring MOFs properties for a wide scope of high-tech applications (high-capacity adsorbents, membranes, thin film devices, catalysis, biomedical imaging, etc.). MOFs have traditionally been used for gas storage and separation...
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...Experiment 7: Lipid Extraction I. Abstract Lipids are biomolecules that are used primarily for structural components of the cell, signaling molecules and energy storage purposes. Lipids are naturally occurring esters of long chain fatty acids with both hydrophobic chains, which is insoluble to polar organic solvents and hydrophilic chains which is soluble to polar organic solvents. Because of this conformation, they can assume a wide range of complex structures including fused rings. Lipids can be isolated from cells through different techniques and their presence can be tested through different qualitative tests. The sample choice is egg yolk and was used as a source of lipids in the experiment. Liquid-liquid extraction, separation of the organic and aqueous layer was used to extract the supernatant or extract. Also, thin layer chromatography or TLC was used to separate the different lipid components by using the Rf values computed. The farther the distance traveled by the compound (higher Rf), the more nonpolar the component, while the smaller the distance traveled, the more polar the component (lower Rf). Lecithin and cholesterol was not able to travel the plate. After, the isolated lipid was subjected to qualitative tests such as Acrolein test, test for phosphates, Leibermann-Burchard test and test for unsaturation. Acrolein tests determine the presence of glycerin; the test for phosphate detects phosphate groups in the structure of the lipid, Leibermann-Burchard uses cholesterol...
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...of 90-82-4. Psuedoephedrine contains three functional groups: amine, hydroxyl, and ethyl in its ring; it also has one stereogenic carbon. The enantiomer of pseudoephedrine is ephedrine, and this substance can form two other diastereomers as well. Pseudoephedrine contains covalent bonds (both and double) and hydrogen bonds. A two-dimensional and three-dimensional structure are given below. [pic] [pic] Psuedoephedrine is also synthesized in various ways, sometimes with methods that add an amide to its structure in order to alter its medicinal effect. One of the most efficient techniques for synthesizing pseudoephedrine is given below: [pic] Reagents and conditions: (i) (CH2O)n, PTSA, benzene, reflux, 1 h; (ii) 1 equiv. NaBH4, MeOH, 2 h; (iii) PhMgBr, THF, 0°C–rt, 3 h; (iv) (CH2O)n, PTSA, benzene, reflux, 1 h; (v) NaCNBH3/TMSCl, CH3CN, rt, 30 min; (vi) conc. HCl, reflux, 2 h Pseudoephedrine is originally obtained as an alkaloid from the Oriental plant genus of Ephedra; as shown above, however, it can also be prepared artificially. The most common method of creating pseudoephedrine today is from yeast fermentation of dextrose in the presence of benzaldehyde. Typically pseudoephedrine exists as a white crystalline, odorless powder with a melting point of 182-182.5ºC. Although it is insoluble in alcohol, it is highly soluble in water and has a molecular weight of 201.70 amu. Pseudoephedrine has a pH around 4.5-6, and the drug is generally very stable under ...
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...J. Org. Chem. 1985,50, 910-912 910 Scheme H I a H N+ C02Et 7c. d H (CHz),, s 0 Sc, d COzEt 8 ( I c , n = l ; d , n = 2. to pyrazolinones 6a,b together with ylides 5a,b as minor products. Bridged 2-pyrazolin-bones 6a,b, whose structures are supported by 'H and 13C NMR spectroscopy, show two strong infrared absorption bands in the 17001800-cm-' range. The first band (1740 cm-') is assigned to the ester carbonyl while we attribute the second one (1765 cm-' for 6a and 1760 cm-l for 6b) to the amide carbonyl. These abnormal high values for an amide band reveal, in accordance with Bredt's rule, an important inhibition of the N-C=O resonance in these N-bridgehead lactams." On the other hand, ' NMR spectra of the crude maH terials obtained from diesters 4c,d at 390-400 "C showed the characteristic signals of a terminal vinyl group suggesting that an elimination reaction follows or competes with the [1,4] migration. Flash column chromatography of the mixture resulting from the thermolysis of the piperidine derivative 4c afforded besides the pyrazolinone 6c12an isomeric N-alkenyl compound whose spectroscopic datal3support the hydroxy-bpyrazole structure 7c. The analogous elimination product 7d formed in lower yield (15% estimation on the basis of 'H NMR spectra) could not be isolated. Pyrazolinone 6c submitted to flow pyrolysis at 400 O C was recovered unchanged. Thus hydroxy-bpyrazoles 7c,d result from an intramolecular elimination...
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...Structures, Biosynthesis and Biofunctions of Iron-sulfer proteins Yiming Chen, Brown University, May 11th, 2011 I. Introduction Iron-sulfur proteins are the proteins which contain iron-sulfur clusters, like sulfide-linked di-, tri-, and tetrairon centers with various oxidative states 1. An excess of 120 distinct types of enzymes and proteins are known to contain Fe-S clusters2. Iron-sulfur proteins are known for the role of the oxidation-reduction reactions of mitochondrial electron transportation. They are also discovered in a series of metalloproteins procedures, for example, ferredoxins 3, Coenzyme Qcytochrome c reductase 4, succinate-coenzyme Q reductase 5 and nitrogenase 6. The iron-sulfur proteins have many functions including catalysis, generate radicals, and also can play as sulfur donors in the biosynthesis of lipoic acid and biotin. Additionally some of the Fe-S proteins are able to regulate the gene expression. Furthermore, the discoveries of new iron-sulfur proteins and iron-sulfur clusters has led to lots of interests of their amazing functional and structural diversity, which reflects the versatility of both iron and sulfur in biochemical processes. Since these iron-sulfur proteins are vey common on the metabolic pathways of most organisms, it leads some scientific interests that iron-sulfur compounds had a significant role in the origin of life in the Iron-sulfur world theory 7. Thus theory claims that the early life on earth probaby formed on the...
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...ARTICLES PUBLISHED ONLINE: 15 DECEMBER 2014 | DOI: 10.1038/NCHEM.2131 Copper-catalysed selective hydroamination reactions of alkynes Shi-Liang Shi and Stephen L. Buchwald* The development of selective reactions that utilize easily available and abundant precursors for the efficient synthesis of amines is a long-standing goal of chemical research. Despite the centrality of amines in a number of important research areas, including medicinal chemistry, total synthesis and materials science, a general, selective and step-efficient synthesis of amines is still needed. Here, we describe a set of mild catalytic conditions utilizing a single copper-based catalyst that enables the direct preparation of three distinct and important amine classes (enamines, α-chiral branched alkylamines and linear alkylamines) from readily available alkyne starting materials with high levels of chemo-, regio- and stereoselectivity. This methodology was applied to the asymmetric synthesis of rivastigmine and the formal synthesis of several other pharmaceutical agents, including duloxetine, atomoxetine, fluoxetine and tolterodine. C omplex organic molecules play a crucial role in the study and treatment of disease. The extent to which they can be utilized in these endeavours depends on the efficient and selective chemical methods for their construction1. Amines are widely represented in biologically active natural products and medicines2 (a small selection of which are shown in Fig. 1a). Consequently, the selective...
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