Conjugated Systems When the P Orbitals of Double Bonds Are On
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Analysis of Trace Hydrocarbon Impurities in 1,3-Butadiene Using Optimized Rt®-Alumina BOND/MAPD PLOT Columns by Rick Morehead, Jan Pijpelink, Jaap De Zeeuw, Tom Vezza
Petroleum & Petrochemical Applications Analysis of Trace Hydrocarbon Impurities in 1,3-Butadiene Using Optimized Rt®-Alumina BOND/MAPD PLOT Columns By Rick Morehead, Jan Pijpelink, Jaap de Zeeuw, Tom Vezza Abstract Identifying and quantifying trace impurities in 1,3-butadiene is critical in producing high quality synthetic rubber products. Stan- dard analytical methods employ alumina PLOT columns which yield good resolution for low molecular weight hydrocarbons, but suffer from irreproducibility and poor sensitivity for polar hydrocarbons. In this study, Rt®-Alumina BOND/MAPD PLOT columns were used to separate both common light polar contaminants, including methyl acetylene and propadiene, as well as 4-vinylcy- clohexene, which is a high molecular weight impurity that normally requires a second test on an alternative column. By using an extended temperature program that employs the full thermal range of the column, 4-vinylcyclohexene, as well as all of the typical low molecular weight impurities in 1,3-butadiene, can be analyzed in a single test. Introduction 1,3-butadiene is typically isolated from products of the naphtha steam cracking process. Prior to purification, 1,3-butadiene can be contaminated with significant amounts of isobutene as well as other C4 isomers. In addition to removing these C4 isomeric contaminants during purification, it is also important that 1,3-butadiene be free of propadiene and methyl acetylene, which can interfere with catalytic polymerization. Alumina PLOT columns are the most commonly used GC column for this application, but the determination of polar hydrocarbon impurities at trace levels can be quite challenging and is highly dependent on the deactiva- tion of the alumina surface. -
Next Generation PLOT Alumina Technology for Accurate Measurement of Trace Polar Hydrocarbons in Hydrocarbon Streams
Next generation PLOT alumina technology for accurate measurement of trace polar hydrocarbons in hydrocarbon streams Jaap de Zeeuw, Tom Vezza, Bill Bromps, Rick Morehead and Gary Stidsen Restek Corporation, Bellefonte, USA 1 Next generation PLOT alumina technology for accurate measurement of trace polar hydrocarbons in hydrocarbon streams Jaap de Zeeuw, Tom Vezza, Bill Bromps, Rick More head and Gary Stidsen Restek Corporation Summary In light hydrocarbon analysis, the separation and detection of traces of polar hydrocarbons like acetylene, propadiene and methyl acetylene is very important. Using commercial alumina columns with KCl or Na2SO4 deactivation, often results in low response of polar hydrocarbons. Additionally, challenges are observed in response-in time stability. Solutions have been proposed to maximize response for components like methyl acetylene and propadiene, using alumina columns that were specially deactivated. Operating such columns showed still several challenges: Due to different deactivations, the retention and loadability of such alumina columns has been drastically reduced. A new Alumina deactivation technology was developed that combined the high response for polar hydrocarbon with maintaining the loadability. This allows the high response for components like methyl acetylene, acetylene and propadiene, also to be used for impurity analysis as well as TCD type applications. Such columns also showed excellent stability of response in time, which was superior then existing solutions. Additionally, it was observed that such alumina columns could be used up to 250 C, extending the Tmax by 50C. This allows higher hydrocarbon elution, faster stabilization and also widens application scope of any GC where multiple columns are used. In this poster the data is presented showing the improvements made in this important application field. -
BENZENE Disclaimer
United States Office of Air Quality EPA-454/R-98-011 Environmental Protection Planning And Standards June 1998 Agency Research Triangle Park, NC 27711 AIR EPA LOCATING AND ESTIMATING AIR EMISSIONS FROM SOURCES OF BENZENE Disclaimer This report has been reviewed by the Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, and has been approved for publication. Mention of trade names and commercial products does not constitute endorsement or recommendation of use. EPA-454/R-98-011 ii TABLE OF CONTENTS Section Page LIST OF TABLES.....................................................x LIST OF FIGURES.................................................. xvi EXECUTIVE SUMMARY.............................................xx 1.0 PURPOSE OF DOCUMENT .......................................... 1-1 2.0 OVERVIEW OF DOCUMENT CONTENTS.............................. 2-1 3.0 BACKGROUND INFORMATION ...................................... 3-1 3.1 NATURE OF POLLUTANT..................................... 3-1 3.2 OVERVIEW OF PRODUCTION AND USE ......................... 3-4 3.3 OVERVIEW OF EMISSIONS.................................... 3-8 4.0 EMISSIONS FROM BENZENE PRODUCTION ........................... 4-1 4.1 CATALYTIC REFORMING/SEPARATION PROCESS................ 4-7 4.1.1 Process Description for Catalytic Reforming/Separation........... 4-7 4.1.2 Benzene Emissions from Catalytic Reforming/Separation .......... 4-9 4.2 TOLUENE DEALKYLATION AND TOLUENE DISPROPORTIONATION PROCESS ............................ 4-11 4.2.1 Toluene Dealkylation -
Supplement of Compilation and Evaluation of Gas Phase Diffusion Coefficients of Reactive Trace Gases in the Atmosphere
Supplement of Atmos. Chem. Phys., 15, 5585–5598, 2015 http://www.atmos-chem-phys.net/15/5585/2015/ doi:10.5194/acp-15-5585-2015-supplement © Author(s) 2015. CC Attribution 3.0 License. Supplement of Compilation and evaluation of gas phase diffusion coefficients of reactive trace gases in the atmosphere: Volume 2. Diffusivities of organic compounds, pressure-normalised mean free paths, and average Knudsen numbers for gas uptake calculations M. J. Tang et al. Correspondence to: M. J. Tang ([email protected]) and M. Kalberer ([email protected]) The copyright of individual parts of the supplement might differ from the CC-BY 3.0 licence. Table of Contents 1 Alkanes and cycloalkanes ............................................................................................ 1 1.1 CH 4 (methane), C 2H6 (ethane), and C 3H8 (propane) ............................................. 1 1.2 C 4H10 (butane, methyl propane) ............................................................................ 3 1.3 C 5H12 (n-pentane, methyl butane, dimethyl butane) ............................................. 5 1.4 C 6H14 (n-hexane, 2,3-dimethyl butane) ................................................................ 7 1.5 C 7H16 (n-heptane, 2,4-dimethyl pentane).............................................................. 9 1.6 C 8H18 (n-octane, 2,2,4-trimethyl pentane) .......................................................... 11 1.7 C 9H20 (n-nonane), C 10 H22 (n-decane, 2,3,3-trimethyl heptane) and C 12 H26 (n- dodecane) ................................................................................................................. -
ETHYLENE PLANT ENHANCEMENT (April 2001)
Abstract Process Economics Program Report 29G ETHYLENE PLANT ENHANCEMENT (April 2001) The prospects for ethylene demand remain strong but much of the future increase in production capacity may come from incremental enhancement of existing plants, rather than from new “grass-roots” production facilities. Steam cracking for ethylene originated as early as the 1920s and was commercialized in the 1950s. The importance of ethylene continues to drive research and development of this technology along with the exploration of nonconventional technologies in order to achieve higher yields of olefins and lower capital and operating costs. However, as recently discussed in PEP Report 29F, Ethylene by Nonconventional Processes (August 1998), it is unlikely nonconventional processes will replace steam cracking for ethylene production in the foreseeable future. This study examines potential improvements in conventional steam cracker operations with emphasis on improving the competitive edge of existing plants. Ethane, LPG and naphtha are the dominant steam cracker feedstocks. Natural gas condensate is abundant in North America and the Middle East while naphtha is commonly used in Asia and Europe. Since the 1970s many new ethylene plants have been built with feedstock flexibility. In PEP Report 220, Ethylene Feedstock Outlook (May 1999), SRIC currently projects that generally ethylene feedstocks supply will be adequate over the next decade even considering that the demand for ethylene is increasing twice as fast as petroleum refining (4- 5%/year versus 2%/year). Significant technological developments exist for all sections of the ethylene steam cracker that could be implemented in plant revamps. Examples include new large capacity yet compact and efficient furnaces; coke inhibition technology; larger, more efficient compressors; fractionation schemes; mixed refrigerants; and advance control and optimization systems. -
Development of Metal-Catalyzed Reactions of Allenes with Imines and the Investigation of Brθnsted Acid Catalyzed Ene Reactions
DEVELOPMENT OF METAL-CATALYZED REACTIONS OF ALLENES WITH IMINES AND THE INVESTIGATION OF BRΘNSTED ACID CATALYZED ENE REACTIONS BY LINDSEY O. DAVIS A Dissertation Submitted to the Graduate Faculty of WAKE FOREST UNIVERSITY GRADUATE SCHOOL OF ARTS AND SCIENCES in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY in the Department of Chemistry December 2009 Winston-Salem, North Carolina Approved By: Paul B. Jones, Ph.D., Advisor ____________________________ Examining Committee: Christa L. Colyer, Ph.D., chair ____________________________ S. Bruce King, Ph. D. _______________________________ Dilip K. Kondepudi, Ph.D. _______________________________ Suzanne L. Tobey, Ph.D. _______________________________ ACKNOWLEDGMENTS I must first acknowledge my family for their support throughout my education. My mother has always encouraged me to ask questions and seek answers, which has guided my inquisitive nature as a scientist. My grandparents have taught me the importance of character and my father taught me the value in hard work. I’d also like to thank my husband for moving away from Georgia, a sacrifice I greatly appreciate. Also, his cheerful disposition helped me stay relatively positive, especially when I had bad research days. My friends also played a very important role in keeping me positive during my time at Wake. Particularly my roommates put up with me more than most. I’d like to thank Lauren Eiter for her sense of humor, Tara Weaver for her taste in books and movies, and Jenna DuMond, for her encouragement and loyalty. Also I’ve made lifetime friends with Meredith and Kavita, and even though they left me at Wake, they were always willing to offer their support. -
Supporting Information for Modeling the Formation and Composition Of
Supporting Information for Modeling the Formation and Composition of Secondary Organic Aerosol from Diesel Exhaust Using Parameterized and Semi-explicit Chemistry and Thermodynamic Models Sailaja Eluri1, Christopher D. Cappa2, Beth Friedman3, Delphine K. Farmer3, and Shantanu H. Jathar1 1 Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA, 80523 2 Department of Civil and Environmental Engineering, University of California Davis, Davis, CA, USA, 95616 3 Department of Chemistry, Colorado State University, Fort Collins, CO, USA, 80523 Correspondence to: Shantanu H. Jathar ([email protected]) Table S1: Mass speciation and kOH for VOC emissions profile #3161 3 -1 - Species Name kOH (cm molecules s Mass Percent (%) 1) (1-methylpropyl) benzene 8.50×10'() 0.023 (2-methylpropyl) benzene 8.71×10'() 0.060 1,2,3-trimethylbenzene 3.27×10'(( 0.056 1,2,4-trimethylbenzene 3.25×10'(( 0.246 1,2-diethylbenzene 8.11×10'() 0.042 1,2-propadiene 9.82×10'() 0.218 1,3,5-trimethylbenzene 5.67×10'(( 0.088 1,3-butadiene 6.66×10'(( 0.088 1-butene 3.14×10'(( 0.311 1-methyl-2-ethylbenzene 7.44×10'() 0.065 1-methyl-3-ethylbenzene 1.39×10'(( 0.116 1-pentene 3.14×10'(( 0.148 2,2,4-trimethylpentane 3.34×10'() 0.139 2,2-dimethylbutane 2.23×10'() 0.028 2,3,4-trimethylpentane 6.60×10'() 0.009 2,3-dimethyl-1-butene 5.38×10'(( 0.014 2,3-dimethylhexane 8.55×10'() 0.005 2,3-dimethylpentane 7.14×10'() 0.032 2,4-dimethylhexane 8.55×10'() 0.019 2,4-dimethylpentane 4.77×10'() 0.009 2-methylheptane 8.28×10'() 0.028 2-methylhexane 6.86×10'() -
Ketenes 25/01/2014 Part 1
Baran Group Meeting Hai Dao Ketenes 25/01/2014 Part 1. Introduction Ph Ph n H Pr3N C A brief history Cl C Ph + nPr NHCl Ph O 3 1828: Synthesis of urea = the starting point of modern organic chemistry. O 1901: Wedekind's proposal for the formation of ketene equivalent (confirmed by Staudinger 1911) Wedekind's proposal (1901) 1902: Wolff rearrangement, Wolff, L. Liebigs Ann. Chem. 1902, 325, 129. 2 Wolff adopt a ketene structure in 1912. R 2 hν R R2 1905: First synthesis and characterization of a ketene: in an efford to synthesize radical 2, 1 ROH R C Staudinger has synthesized diphenylketene 3, Staudinger, H. et al., Chem. Ber. 1905, 1735. N2 1 RO CH or Δ C R C R1 1907-8: synthesis and dicussion about structure of the parent ketene, Wilsmore, O O J. Am. Chem. Soc. 1907, 1938; Wilsmore and Stewart Chem. Ber. 1908, 1025; Staudinger and Wolff rearrangement (1902) O Klever Chem. Ber. 1908, 1516. Ph Ph Cl Zn Ph O hot Pt wire Zn Br Cl Cl CH CH2 Ph C C vs. C Br C Ph Ph HO O O O O O O O 1 3 (isolated) 2 Wilsmore's synthesis and proposal (1907-8) Staudinger's synthesis and proposal (1908) wanted to make Staudinger's discovery (1905) Latest books: ketene (Tidwell, 1995), ketene II (Tidwell, 2006), Science of Synthesis, Vol. 23 (2006); Latest review: new direactions in ketene chemistry: the land of opportunity (Tidwell et al., Eur. J. Org. Chem. 2012, 1081). Search for ketenes, Google gave 406,000 (vs. -
Synthesis of Allenes by Isomerization Reactions
3 1 Synthesis of Allenes by Isomerization Reactions A. Stephen K. Hashmi 1.1 Introduction Isomerization reactions are associated with a change in either the connectivity (the constitution) of the molecule or the steric arrangement of atoms or groups in the molecule. However, no change of the empirical formula is involved. Thus in isomer- ization reactions leading to allenes, the 1,2-diene substructure that is characteristic of this class of compounds has to be formed by one of the following reactions (Scheme 1.1): (a) Migration of a non-cumulated p-bond into cumulation with a second p-bond. The non-cumulated p-bonds can either be an alkyne (Reaction A) or a conjugat- ed or isolated diene (Reaction B). If in Reaction A the group X = H this is a pro- totropic rearrangement; another possibility would be a sigmatropic rearrange- ment in which X typically is a two- or three-atomic unsaturated moiety. These two cases are the most important isomerization reactions leading to allenes. Another priciple that would also fall into this category would be the rearrange- ment of one allene to another. (b) Transformation of a ring (a double bond equivalent) to a p-bond by a kind of intramolecular elimination process (Reaction C) or an electrocyclic ring opening (Reaction D). (c) Another option would be the addition of an intramolecular nucleophile to a con- jugated, alkyne-containing system such as a 1,3-enyne (Reaction E) or a higher cumulene (Reaction F). (d) A substitution would only fall into the category of isomerization if it is entirely intramolecular; both the attacking and the leaving group would need to remain part of the molecule. -
Identification of Gas-Phase Pyrolysis Products in A
Atmos. Meas. Tech., 12, 763–776, 2019 https://doi.org/10.5194/amt-12-763-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Identification of gas-phase pyrolysis products in a prescribed fire: first detections using infrared spectroscopy for naphthalene, methyl nitrite, allene, acrolein and acetaldehyde Nicole K. Scharko1, Ashley M. Oeck1, Russell G. Tonkyn1, Stephen P. Baker2, Emily N. Lincoln2, Joey Chong3, Bonni M. Corcoran3, Gloria M. Burke3, David R. Weise3, Tanya L. Myers1, Catherine A. Banach1, David W. T. Griffith4, and Timothy J. Johnson1 1Pacific Northwest National Laboratories, Richland, WA, USA 2Rocky Mountain Research Station, USDA Forest Service, Missoula, MT, USA 3Pacific Southwest Research Station, USDA Forest Service, Riverside, CA, USA 4Centre for Atmospheric Chemistry, University of Wollongong, Wollongong NSW 2522, Australia Correspondence: Timothy J. Johnson ([email protected]) Received: 1 October 2018 – Discussion started: 13 November 2018 Revised: 16 January 2019 – Accepted: 16 January 2019 – Published: 1 February 2019 Abstract. Volatile organic compounds (VOCs) are emitted ventive tool to reduce hazardous fuel buildups in an effort to from many sources, including wildland fire. VOCs have re- reduce or eliminate the risk of such wildfires (Fernandes and ceived heightened emphasis due to such gases’ influential Botelho, 2003). Understanding the products associated with role in the atmosphere, as well as possible health effects. the burning of biomass has received considerable attention We have used extractive infrared (IR) spectroscopy on re- since the emissions can markedly impact the atmosphere. cent prescribed burns in longleaf pine stands and herein re- Fourier-transform infrared (FTIR) spectroscopy is one tech- port the first detection of five compounds using this tech- nique that has been extensively used to identify and quantify nique. -
Insertion Reactions of Allenes Giving Vinyl Complexes
4896 Organometallics 2005, 24, 4896-4898 Insertion Reactions of Allenes Giving Vinyl Complexes Peng Xue, Jun Zhu, Herman S. Y. Hung, Ian D. Williams, Zhenyang Lin,* and Guochen Jia* Department of Chemistry and Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Received August 6, 2005 Summary: Treatment of OsHCl(PPh3)3 with allenes Scheme 1 CH2dCdCHR at room temperature in benzene produced the vinyl complexes OsCl(C(CH3)dCHR)(CH2dCdCHR)- 3 (PPh3)2, instead of η -allyl complexes as normally ob- served. DFT calculations show that the formation of the vinyl complex is favored kinetically. There has been great interest in transition-metal- catalyzed reactions of allenes.1,2 Insertion of allenes into M-R bonds represents one of the most important fundamental steps in catalytic reactions of allenes. In principle, allenes can undergo insertion reactions with LnM-R to give either transition-metal allyl complexes A or vinyl complexes B, as illustrated in eq 1. The plexes are now well documented. Although catalytic reactions involving insertion of allenes into M-R bonds to give vinyl intermediates were occasionally proposed,6 stoichiometric insertion reactions of allenes with well- defined LnM-R to give vinyl complexes cannot be found in the literature, to the best of our knowledge. In this insertion of allenes into M-R bonds to give allyl work, we wish to report the first examples of formation intermediates has been frequently invoked in the mech- of vinyl complexes from allene insertion reactions. -
Steam Cracking: Chemical Engineering
Steam Cracking: Kinetics and Feed Characterisation João Pedro Vilhena de Freitas Moreira Thesis to obtain the Master of Science Degree in Chemical Engineering Supervisors: Professor Doctor Henrique Aníbal Santos de Matos Doctor Štepánˇ Špatenka Examination Committee Chairperson: Professor Doctor Carlos Manuel Faria de Barros Henriques Supervisor: Professor Doctor Henrique Aníbal Santos de Matos Member of the Committee: Specialist Engineer André Alexandre Bravo Ferreira Vilelas November 2015 ii The roots of education are bitter, but the fruit is sweet. – Aristotle All I am I owe to my mother. – George Washington iii iv Acknowledgments To begin with, my deepest thanks to Professor Carla Pinheiro, Professor Henrique Matos and Pro- fessor Costas Pantelides for allowing me to take this internship at Process Systems Enterprise Ltd., London, a seven-month truly worthy experience for both my professional and personal life which I will certainly never forget. I would also like to thank my PSE and IST supervisors, who help me to go through this final journey as a Chemical Engineering student. To Stˇ epˇ an´ and Sreekumar from PSE, thank you so much for your patience, for helping and encouraging me to always keep a positive attitude, even when harder problems arose. To Prof. Henrique who always showed availability to answer my questions and to meet in person whenever possible. Gostaria tambem´ de agradecer aos meus colegas de casa e de curso Andre,´ Frederico, Joana e Miguel, com quem partilhei casa. Foi uma experienciaˆ inesquec´ıvel que atravessamos´ juntos e cer- tamente que a vossa presenc¸a diaria´ apos´ cada dia de trabalho ajudou imenso a aliviar as saudades de casa.