Structural Determination Of Compounds
|
|
- Darleen Hawkins
- 6 years ago
- Views:
Transcription
1 EXPERIMENT 10 Mass Spectroscopy Structural Determination Of Compounds. Introduction - In mass spectrometry, a substance is bombarded with an electron beam having sufficient energy to fragment the molecule. The positive fragments which are produced (cations and radical cations) are accelerated in a vacuum through a magnetic field and are sorted on the basis of mass-to-charge ratio. Since the bulk of the ions produced in the mass spectrometer carry a unit positive charge, the value m/e is equivalent to the molecular weight of the fragment. The analysis of mass spectroscopy information involves the reassembling of fragments, working backwards to generate the original molecule. A schematic representation of a mass spectrometer is shown below: A very low concentration of sample molecules is allowed to leak into the ionization chamber (which is under a very high vacuum) where they are bombarded by a high-energy electron beam. The molecules fragment and the positive ions produced are accelerated through a charged array into an analyzing tube. The path of the charged molecules is bent by an applied magnetic field. Ions having low mass (low momentum) will be deflected most by this field and will collide with the walls of the analyzer. Likewise, high momentum ions will not be deflected enough and will also collide with the analyzer wall. Ions having the proper mass-to-charge ratio, however, will follow the path of the analyzer, exit through the slit and collide with the Collector. This generates an electric current, which is then amplified and detected. By varying the strength of the magnetic field, the mass-to-charge ratio, which is analyzed, can be continuously varied. The output of the mass spectrometer shows a plot of relative intensity vs. the mass-to-charge ratio (m/e). The most intense peak in the spectrum is termed the base peak and all others are reported relative to its intensity. The peaks themselves are typically very sharp, and are often simply represented as vertical lines. The process of fragmentation follows simple and predictable chemical pathways and the ions, which are formed, will reflect the most stable cations and radical cations, which that molecule can form. The highest 1
2 molecular weight peak observed in a spectrum will typically represent the parent molecule, minus an electron, and is termed the molecular ion (M+). Generally, small peaks are also observed above the calculated molecular weight due to the natural isotopic abundance of 13 C, 2 H, etc. Many molecules with especially labile protons do not display molecular ions; an example of this is alcohols, where the highest molecular weight peak occurs at m/e one less than the molecular ion (m-1). Fragments can be identified by their mass-to-charge ratio, but it is often more informative to identify them by the mass which has been lost. That is, loss of a methyl group will generate a peak at m-15; loss of an ethyl, m-29, etc. Click here for a table of common fragments. The mass spectrum of toluene (methyl benzene) is shown below. The spectrum displays a strong molecular ion at m/e = 92, small m+1 and m+2 peaks, a base peak at m/e = 91 and an assortment of minor peaks m/e = 65 and below. The molecular ion, again, represents loss of an electron and the peaks above the molecular ion are due to isotopic abundance. The base peak in toluene is due to loss of a hydrogen atom to form the relatively stable benzyl cation. This is thought to undergo rearrangement to form the very stable tropylium cation, and this strong peak at m/e = 91 is a hallmark of compounds containing a benzyl unit. The minor peak at m/e = 65 represents loss of neutral acetylene from the tropylium ion and the minor peaks below this arise from more complex fragmentation. Common Mass Spectrum Fragments 2
3 Mass Spectrometry - Functional Groups Alkanes: Simple alkanes tend to undergo fragmentation by the initial loss of a methyl group to form a (m-15) species. This carbocation can then undergo stepwise cleavage down the alkyl chain, expelling neutral twocarbon units (ethene). Branched hydrocarbons form more stable secondary and tertiary carbocations, and these peaks will tend to dominate the mass spectrum. Aromatic Hydrocarbons: The fragmentation of the aromatic nucleus is somewhat complex, generating a series of peaks having m/e = 77, 65, 63, etc. While these peaks are difficult to describe in simple terms, they do form a pattern (the "aromatic cluster") that becomes recognizable with experience. If the molecule contains a benzyl unit, the major cleavage will be to generate the benzyl carbocation, which rearranges to form the tropylium ion. Expulsion of acetylene (ethyne) from this generates a characteristic m/e = 65 peak. Aldehydes and Ketones: The predominate cleavage in aldehydes and ketones is loss of one of the side-chains to generate the substituted oxonium ion. This is an extremely favorable cleavage and this ion often represents the base peak in the spectrum. The methyl derivative (CH 3 C O + ) is commonly referred to as the "acylium ion". Another common fragmentation observed in carbonyl compounds (and in nitriles, etc.) involves the expulsion of neutral ethene via a process known as the McLafferty rearrangement, following the general mechanism shown below. Esters, Acids and Amides: As with aldehydes and ketones, the major cleavage observed for these compounds involves expulsion of the "X" group, as shown below, to form the substituted oxonium ion. For carboxylic acids and unsubstituted amides, characteristic peaks at m/e = 45 and 44 are also often observed. 3
4 Alcohols: In addition to losing a proton and hydroxy radical, alcohols tend to lose one of the -alkyl groups (or hydrogens) to form the oxonium ions shown below. For primary alcohols, this generates a peak at m/e = 31; secondary alcohols generate peaks with m/e = 45, 59, 73, etc., according to substitution. Ethers: Following the trend of alcohols, ethers will fragment, often by loss of an alkyl radical, to form a substituted oxonium ion, as shown below for diethyl ether. Halides: Organic halides fragment with simple expulsion of the halogen, as shown below. The molecular ions of chlorine and bromine-containing compounds will show multiple peaks due to the fact that each of these exists as two isotopes in relatively high abundance. Thus for chlorine, the 35 Cl/ 37 Cl ratio is roughly 3.08:1 and for bromine, the 79 Br/ 81 Br ratio is 1.02:1. The molecular ion of a chlorine-containing compound will have two peaks, separated by two mass units, in the ratio 3:1, and a bromine-containing compound will have two peaks, again separated by two mass units, having approximately equal intensities. 4
5 Example (1) A unknown sample of hydrocarbon with only one oxygen, CxHyO Mass Spectrum Analysis: MW = , C 9 H 10 O Degree of unsaturation: D.U. = ( 9 ) ( 10/2) +1 = 5 ( contains a benzene ring) Parent peak : m/z = 134 Base peak : m/z = 91 Structure: IUPAC Name: 3-pentanone (diethyl ketone) MS Fragments: The spectrum shows a moderate molecular ion peak, and a peak at m-15, strongly suggesting the presence of a labile methyl group. The base peak occurs at m/e = 91, which is highly suggestive of a benzyl fragment, which rearranges to form the tropylium cation. The presence of an intense peak at m/e = 43 is also suggestive of the presence of a methyl ketone which can fragment to form the acylium ion. 5
6 Example(2) A unknown sample of hydrocarbon with two oxygen atom, CxHyO 2 Mass Spectrum Analysis: MW = , C 5 H 8 O 2 Degree of unsaturation: D.U. = ( 5 ) ( 8/2) +1 = 2 Parent peak : m/z = 100 Base peak : m/z = 43 Structure: IUPAC Name: 2-propenyl ethanoate (allyl acetate) MS Fragments: The spectrum shows a small molecular ion peak, and a pair of peaks at m/e = 57 and 58. The peak at m/e = 57 corresponds to loss of m/e = 43, which is the base peak and corresponds to the acylium ion (CH 3 C O + ). The m/e = 57 fragment corresponds to C 3 H 5 O, suggesting the original compound was an allyl (-O-CH 2 CH CH) or methylvinyl (-O-CH CHCH 3 ) ester. Either of these would generate the peak observed at m/e = 41. The peak at m/e = 58 corresponds to the protonated m/e = 57 cation radical. 6
7 Example (3) A unknown sample of hydrocarbon with halogen, alkylhalide, CxHyX. ( X = Cl, Br, I) Analysis: C 7 H 12 Br MW = Mass Spectrum Analysis: MW = , C 7 H 7 Br Degree of unsaturation: D.U. = ( 7 ) ( 7/2) (1/2) +1 = 4 Parent peak : m/z = 172 Base peak : m/z = 91 Structure: IUPAC Name: bromomethyl benzene (benzyl bromide) MS Fragments: The spectrum shows two small peaks of equal intensity in the molecular ion region, strongly suggesting that the molecule contains bromine (equal concentrations of the 79 Br and 81 Br isotopes). The base peak represents loss of this bromine to give the peak at m/e = 91, which is highly suggestive of a benzyl fragment, which rearranges to form the tropylium cation. 7
8 EXPERIMENT 10 Mass Spectroscopy Problems Name Instructor Date Problems Sets Please Identify the possible structure in each one of the following problems. 1. An organic compound (A) is composed of carbon, hydrogen and nitrogen, with carbon constituting over 60% of the mass. It shows a molecular ion at m/z=112 amu in the mass spectrum. a) Write a plausible Molecular Formula for compound A. b) How many Rings + Double Bonds must be present in compound A? 2. Another compound, B, composed only of carbon, hydrogen and oxygen, also shows a molecular ion at m/z=112 amu. Write a plausible Molecular Formula for compound B, assuming it has three double bonds and no rings. 3. Compound C is composed only of carbon, hydrogen and oxygen, and shows a molecular ion at m/z=180 amu. Carbon accounts for 60% of the molecular mass. a) Write a plausible Molecular Formula for compound C. b) How many Rings + Double Bonds must be present in compound C? 8
9 4. CxHyO 5. CxHyO 6. CxHyO 2 7. CxHyX ( X = halogen) 8. CxHyO 2 9
10 9. CxHyO CxHy 10
Mass Spectrometry. 2000, Paul R. Young University of Illinois at Chicago, All Rights Reserved
Mass Spectrometry 2000, Paul R. Young University of Illinois at Chicago, All Rights Reserved Mass Spectrometry When a molecule is bombarded with high-energy electrons, one of the process that can occur
More informationMass Spectrometry - Background
Mass Spectrometry - Background In mass spectrometry, a substance is bombarded with an electron beam having sufficient energy to fragment the molecule. The positive fragments which are produced (cations
More informationMass Spectrometry Instrumentation
Mass Spectrometry Instrumentation A mass spectrometer is composed of an inlet system (which introduces the sample to the instrument and vaporizes the sample) A molecular leak (which produces a steady stream
More informationMASS SPECTROSCOPY (MS)
MASS SPECTOSCOPY (MS) Castor seeds icin (toxic protein) INTODUCTION Does not involve absorption of electromagnetic radiation. It is a spectroscopic technique, by virtue of its use in structure elucidation.
More information3 Use of Mass Spectra to Obtain Structural Information
3 Use of Mass Spectra to Obtain Structural Information 1 Mass Spectrometry One of the most sensitive and versatile analytical tools More sensitive than other spectroscopic methods (e.g. IR spectroscopy)
More informationPropose a structure for an alcohol, C4H10O, that has the following
Propose a structure for an alcohol, C4H10O, that has the following 13CNMR spectral data: Broadband _ decoupled 13CNMR: 19.0, 31.7, 69.5 б DEPT _90: 31.7 б DEPT _ 135: positive peak at 19.0 & 31.7 б, negative
More informationMass Spectrometry. Introduction EI-MS and CI-MS Molecular mass & formulas Principles of fragmentation Fragmentation patterns Isotopic effects
Mass Spectrometry Introduction EI-MS and CI-MS Molecular mass & formulas Principles of fragmentation Fragmentation patterns Isotopic effects 1 Introduction to MS Mass spectrometry is the method of analysis
More information2. Separate the ions based on their mass to charge (m/e) ratio. 3. Measure the relative abundance of the ions that are produced
I. Mass spectrometry: capable of providing both quantitative and qualitative information about samples as small as 100 pg (!) and with molar masses in the 10 4-10 5 kdalton range A. The mass spectrometer
More informationCHEM 241 UNIT 5: PART A DETERMINATION OF ORGANIC STRUCTURES BY SPECTROSCOPIC METHODS [MASS SPECTROMETRY]
CHEM 241 UNIT 5: PART A DETERMINATION OF ORGANIC STRUCTURES BY SPECTROSCOPIC METHODS [MASS SPECTROMETRY] 1 Introduction Outline Mass spectrometry (MS) 2 INTRODUCTION The analysis of the outcome of a reaction
More informationOAT Organic Chemistry - Problem Drill 19: NMR Spectroscopy and Mass Spectrometry
OAT Organic Chemistry - Problem Drill 19: NMR Spectroscopy and Mass Spectrometry Question No. 1 of 10 Question 1. Which statement concerning NMR spectroscopy is incorrect? Question #01 (A) Only nuclei
More informationORGANIC - BRUICE 8E CH MASS SPECT AND INFRARED SPECTROSCOPY
!! www.clutchprep.com CONCEPT: PURPOSE OF ANALYTICAL TECHNIQUES Classical Methods (Wet Chemistry): Chemists needed to run dozens of chemical reactions to determine the type of molecules in a compound.
More informationChapter 20. Mass Spectroscopy
Chapter 20 Mass Spectroscopy Mass Spectrometry (MS) Mass spectrometry is a technique used for measuring the molecular weight and determining the molecular formula of an organic compound. Mass Spectrometry
More information15.04.jpg. Mass spectrometry. Electron impact Mass spectrometry
Mass spectrometry Electron impact Mass spectrometry 70 ev = 1614 kcal/mol - contrast with energy from IR (1-10 kcal/mol) or NMR (0.2 cal/mol) - typical C-C bond = 100 kcal/mol Point: lots of energy in
More informationMass Spectroscopy. Dr. Sapna Gupta
Mass Spectroscopy Dr. Sapna Gupta What is Mass Spectroscopy It is an analytical technique for measuring the mass-tocharge ratio (m/z) of ions in the gas phase. Mass spectrometry is our most valuable analytical
More informationTeory of Mass Spectrometry Taslim Ersam
Teory of Mass Spectrometry Taslim Ersam I. Fragmentation Chemistry of Ions 1. ne bond σ-cleavages: a. cleavage of C-CC C C C C b. cleavage of C-heteroatom C Z C Z 15/09/2011 1 I. Fragmentation Chemistry
More informationCHEMISTRY Topic #3: Using Spectroscopy to Identify Molecules: Radicals and Mass Spectrometry (MS) Spring 2018 Dr.
CHEMISTRY 2600 Topic #3: Using Spectroscopy to Identify Molecules: Radicals and Mass Spectrometry (MS) Spring 2018 Dr. Susan Findlay Mass Spectrometry: How Does It Work? In CHEM 1000, you saw that mass
More informationA N I N T R O D U C T I O N T O... MASS SPECTROMETRY. A self-study booklet
A N I N T R O D U C T I O N T O... MASS SPECTROMETRY A self-study booklet 2 Mass Spectrometry MASS SPECTROMETRY Introduction Theory A mass spectrum can be thought of as being the record of the damage done
More informationIdentification of functional groups in the unknown Will take in lab today
Qualitative Analysis of Unknown Compounds 1. Infrared Spectroscopy Identification of functional groups in the unknown Will take in lab today 2. Elemental Analysis Determination of the Empirical Formula
More informationMore information can be found in Chapter 12 in your textbook for CHEM 3750/ 3770 and on pages in your laboratory manual.
CHEM 3780 rganic Chemistry II Infrared Spectroscopy and Mass Spectrometry Review More information can be found in Chapter 12 in your textbook for CHEM 3750/ 3770 and on pages 13-28 in your laboratory manual.
More information12. Structure Determination: Mass Spectrometry and Infrared Spectroscopy
12. Structure Determination: Mass Spectrometry and Infrared Spectroscopy Determining the Structure of an Organic Compound The analysis of the outcome of a reaction requires that we know the full structure
More informationWelcome to Organic Chemistry II
Welcome to Organic Chemistry II Erika Bryant, Ph.D. erika.bryant@hccs.edu Class Syllabus 3 CHAPTER 12: STRUCTURE DETERMINATION 4 What is this solution Soda Tea Coffee??? 5 What is this solution Soda Tea
More information(2) Read each statement carefully and pick the one that is incorrect in its information.
Organic Chemistry - Problem Drill 17: IR and Mass Spectra No. 1 of 10 1. Which statement about infrared spectroscopy is incorrect? (A) IR spectroscopy is a method of structure determination based on the
More informationCHAPTER 2. Fragmentation and Interpretation of Spectra
2.1 Introduction CHAPTER 2 Fragmentation and Interpretation of Spectra Before discussing fragmentation and interpretation, it is important to understand the many ways mass spectra are utilized. For the
More informationChapter 5. Mass spectrometry
ionization and fragmentation Chapter 5. Mass spectrometry which fragmentations? mass and frequency, m/z and count rate Reading: Pavia Chapters 3 and 4 Don t need 3.3 B-D, 3.4 B-D Use the text to clarify
More informationORGANIC - EGE 5E CH UV AND INFRARED MASS SPECTROMETRY
!! www.clutchprep.com CONCEPT: IR SPECTROSCOPY- FREQUENCIES There are specific absorption frequencies in the functional group region that we should be familiar with EXAMPLE: What are the major IR absorptions
More informationMASS SPECTROMETRY: BASIC EXPERIMENT
http://science.widener.edu/svb/massspec/ei.html relative abundance Pavia 8.1-8.5 MASS SPECTROMETRY: BASIC EXPERIMENT scienceaid.co.uk -e Molecule Molecule +. + 2e base peak [Fragments] +. fragment peaks
More informationLecture 14 Organic Chemistry 1
CHEM 232 Organic Chemistry I at Chicago Lecture 14 Organic Chemistry 1 Professor Duncan Wardrop February 25, 2010 1 CHEM 232 Organic Chemistry I at Chicago Mass Spectrometry Sections: 13.24-13.25 2 Spectroscopy
More informationAromatic Hydrocarbons
Aromatic Hydrocarbons Aromatic hydrocarbons contain six-membered rings of carbon atoms with alternating single and double carbon-carbon bonds. The ring is sometimes shown with a circle in the center instead
More informationCHAPTER 6. GC EI and CI Fragmentation and Interpretation of Spectra
1 1 1 1 1 1 1 1 0 1 0 1 CAPTER GC EI and CI Fragmentation and Interpretation of Spectra.1 Introduction Before discussing fragmentation and interpretation, it is important to understand the many ways mass
More informationLecture notes in EI-Mass spectrometry. By Torben Lund
1 Lecture notes in EI-Mass spectrometry By Torben Lund RUC 2015 1. Basic advise: 1) Identify the mole peak M +. 2) Nitogen rule: Determine number of N 3) A+2 elements: Cl, Br, S, Si 4) N C = 100 [M+1]/([M]
More informationChapter 12 Mass Spectrometry and Infrared Spectroscopy
Organic Chemistry, 6 th Edition L. G. Wade, Jr. Chapter 12 Mass Spectrometry and Infrared Spectroscopy Jo Blackburn Richland College, Dallas, TX Dallas County Community College District 2006, Prentice
More informationChem 1075 Chapter 19 Organic Chemistry Lecture Outline
Chem 1075 Chapter 19 Organic Chemistry Lecture Outline Slide 2 Introduction Organic chemistry is the study of and its compounds. The major sources of carbon are the fossil fuels: petroleum, natural gas,
More informationMass Spectrometry. General Principles
General Principles Mass Spectrometer: Converts molecules to ions Separates ions (usually positively charged) on the basis of their mass/charge (m/z) ratio Quantifies how many units of each ion are formed
More informationMass Spectrometry (MS)
Kevin Burgess, February 20, 2017 1 Mass Spectrometry (MS) from chapter(s) in the recommended text A. Introduction Kevin Burgess, February 20, 2017 2 B. Components f Mass Spectrometers mass-to-charge. molecular
More informationMass Spectrometry: Introduction
Mass Spectrometry: Introduction Chem 8361/4361: Interpretation of Organic Spectra 2009 Andrew Harned & Regents of the University of Minnesota Varying More Mass Spectrometry NOT part of electromagnetic
More informationFri 6 Nov 09. More IR Mass spectroscopy. Hour exam 3 Fri Covers Chaps 9-12 Wednesday: Review
Fri 6 Nov 09 our exam 3 Fri 11-13 Covers Chaps 9-12 Wednesday: Review More IR Mass spectroscopy Good web site for IR, Mass, NMR spectra: http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/cre_index.cgi?lang=eng
More informationChapter 12 Structure Determination: Mass Spectrometry and Infrared Spectroscopy
Chapter 12 Structure Determination: Mass Spectrometry and Infrared Spectroscopy Figure 12.1 - The electron-ionization, magneticsector mass spectrometer Representing the Mass Spectrum Base Peak Parent
More information5. Carbon-13 NMR Symmetry: number of chemically different Carbons Chemical Shift: chemical environment of Carbons (e- rich or e- poor)
Qualitative Analysis of Unknown Compounds 1. Infrared Spectroscopy Identification of functional groups in the unknown All functional groups are fair game (but no anhydride or acid halides, no alkenes or
More informationsample was a solution that was evaporated in the spectrometer (such as with ESI-MS) ions such as H +, Na +, K +, or NH 4
Introduction to Spectroscopy V: Mass Spectrometry Basic Theory: Unlike other forms of spectroscopy used in structure elucidation of organic molecules mass spectrometry does not involve absorption/emission
More informationORGANIC - CLUTCH CH ANALYTICAL TECHNIQUES: IR, NMR, MASS SPECT
!! www.clutchprep.com CONCEPT: PURPOSE OF ANALYTICAL TECHNIQUES Classical Methods (Wet Chemistry): Chemists needed to run dozens of chemical reactions to determine the type of molecules in a compound.
More informationOrganic Chemistry. Alkynes
For updated version, please click on http://ocw.ump.edu.my Organic Chemistry Alkynes by Dr. Seema Zareen & Dr. Izan Izwan Misnon Faculty Industrial Science & Technology seema@ump.edu.my & iezwan@ump.edu.my
More informationMass spectrometry as analytical tool in catalysis research
Mass spectrometry as analytical tool in catalysis research Katrin Pelzer Functional Characterization AC, FHI-MPG Berlin 17/11/2006 Mass Spectrometry Modern Methods in Heterogeneous Catalysis Research K.
More informationCHM 223 Organic Chemistry I Prof. Chad Landrie. Lecture 10: September 20, 2018 Ch. 12: Spectroscopy mass spectrometry infrared spectroscopy
M 223 Organic hemistry I Prof. had Landrie Lecture 10: September 20, 2018 h. 12: Spectroscopy mass spectrometry infrared spectroscopy i>licker Question onsider a solution that contains 65g R enantiomer
More information12.1 The Nature of Organic molecules
12.1 The Nature of Organic molecules Organic chemistry: : The chemistry of carbon compounds. Carbon is tetravalent; it always form four bonds. Prentice Hall 2003 Chapter One 2 Organic molecules have covalent
More informationORGANIC - CLUTCH CH ANALYTICAL TECHNIQUES: IR, NMR, MASS SPECT
!! www.clutchprep.com CONCEPT: PURPOSE OF ANALYTICAL TECHNIQUES Classical Methods (Wet Chemistry): Chemists needed to run dozens of chemical reactions to determine the type of molecules in a compound.
More informationChapter 25: The Chemistry of Life: Organic and Biological Chemistry
Chemistry: The Central Science Chapter 25: The Chemistry of Life: Organic and Biological Chemistry The study of carbon compounds constitutes a separate branch of chemistry known as organic chemistry The
More informationUnit 5: Organic Chemistry
Unit 5: Organic Chemistry Organic chemistry: discipline in chemistry focussing strictly on the study of hydrocarbons compounds made up of carbon & hydrogen Organic compounds can contain other elements
More informationChapter 1 Reactions of Organic Compounds. Reactions Involving Hydrocarbons
Chapter 1 Reactions of Organic Compounds Reactions Involving Hydrocarbons Reactions of Alkanes Single bonds (C-C) are strong and very hard to break, therefore these compounds are relatively unreactive
More informationORGANIC - EGE 5E CH. 2 - COVALENT BONDING AND CHEMICAL REACTIVITY
!! www.clutchprep.com CONCEPT: HYBRID ORBITAL THEORY The Aufbau Principle states that electrons fill orbitals in order of increasing energy. If carbon has only two unfilled orbitals, why does it like to
More informationChapter 11. Introduction to Organic Chemistry
hapter 11 Introduction to rganic hemistry Properties of arbon and its compounds 2 Properties of arbon and its compounds 3 Properties of arbon and its compounds 4 Properties of arbon and its compounds 5
More informationChapter 9. Organic Chemistry: The Infinite Variety of Carbon Compounds. Organic Chemistry
Chapter 9 Organic Chemistry: The Infinite Variety of Carbon Compounds Organic Chemistry Organic chemistry is defined as the chemistry of carbon compounds. Of tens of millions of known chemical compounds,
More informationFAMILIES of ORGANIC COMPOUNDS
1 SCH4U October 2016 Organic Chemistry Chemistry of compounds that contain carbon (except: CO, CO 2, HCN, CO 3 - ) Carbon is covalently bonded to another carbon, hydrogen and possibly to oxygen, a halogen
More informationOrganic Chemistry. Organic chemistry is the chemistry of compounds containing carbon.
Organic Chemistry Organic Chemistry Organic chemistry is the chemistry of compounds containing carbon. In this chapter we will discuss the structural features of organic molecules, nomenclature, and a
More informationElectronegativity Scale F > O > Cl, N > Br > C, H
Organic Chem Chapter 12 Alkanes Organic chemistry is the study of carbon compounds. Carbon has several properties that are worth discussing: Tetravalent Always forms 4 bonds Can form multiple bonds (double
More informationDetailed Course Content
Detailed Course Content Chapter 1: Carbon Compounds and Chemical Bonds The Structural Theory of Organic Chemistry 4 Chemical Bonds: The Octet Rule 6 Lewis Structures 8 Formal Charge 11 Resonance 14 Quantum
More informationChapter 22. Organic and Biological Molecules
Chapter 22 Organic and Biological Molecules The Bonding of Carbon Organic chemistry is the chemistry of compounds containing carbon. Because carbon can form single, double, and triple bonds, the following
More informationPaper 12: Organic Spectroscopy
Subject Chemistry Paper No and Title Module No and Title Module Tag Paper 12: Organic Spectroscopy 31: Combined problem on UV, IR, 1 H NMR, 13 C NMR and Mass - Part III CHE_P12_M31 TABLE OF CONTENTS 1.
More informationCHEM 112 Name: (Last) (First). Section No.: VISUALIZING ORGANIC REACTIONS THROUGH USE OF MOLECULAR MODELS
CHEM 112 Name: (Last) (First). Section No.: VISUALIZING ORGANIC REACTIONS THROUGH USE OF MOLECULAR MODELS 1) HYDROCARBONS: a. Saturated Hydrocarbons: Construct a model for propane, C 3 H 8, using black
More informationQualitative Organic Analysis CH 351 Mass Spectrometry
Qualitative Organic Analysis CH 351 Mass Spectrometry Bela Torok Department of Chemistry University of Massachusetts Boston Boston, MA General Aspects Theoretical basis of mass spectrometry Basic Instrumentation
More informationQualitative Analysis of Unknown Compounds
Qualitative Analysis of Unknown Compounds 1. Infrared Spectroscopy Identification of functional groups in the unknown All functional groups are fair game (but no anhydride or acid halides, no alkenes or
More informationL.7. Mass Spectrum Interpretation
L.7. Mass Spectrum Interpretation Fragmentation reactions Spectrum interpretation Confirmation of ion structural assignment Biomolecule dissociation Fragmentation reactions 1. Fragmentation reactions of
More informationThe International Union of Pure and Applied Chemistry has developed a system of rules for naming organic molecules.
HYDRCARBNS AND THEIR DERIVATIVES The field of organic chemistry includes the study of hydrocarbons (compounds composed of carbon and hydrogen atoms covalently bonded together) and their derivatives (variations
More informationChemistry 14C Winter 2017 Exam 2 Solutions Page 1
Chemistry 14C Winter 2017 Exam 2 Solutions Page 1 Statistics: High score, average, and low score will be posted on the course web site after exam grading is complete. Some questions have more than one
More informationChapter Two mass spectra are shown. One corresponds to 2-methyl-2-pentene; the other, to 2-hexene. Which is which? Explain.
hapter 12 12.1 Write as many molecular formulas as you can for compounds that have the following molecular ions in their mass spectra. Assume that all the compounds contain and and that may or may not
More informationBIOB111 - Tutorial activities for session 8
BIOB111 - Tutorial activities for session 8 General topics for week 4 Session 8 Physical and chemical properties and examples of these functional groups (methyl, ethyl in the alkyl family, alkenes and
More informationName Date Class. aryl halides substitution reaction
23.1 INTRODUCTION TO FUNCTIONAL GROUPS Section Review Objectives Explain how organic compounds are classified Identify the IUPAC rules for naming halocarbons Describe how halocarbons can be prepared Vocabulary
More informationCarbon Compounds. Chemical Bonding Part 2
Carbon Compounds Chemical Bonding Part 2 Introduction to Functional Groups: Alkanes! Alkanes Compounds that contain only carbons and hydrogens, with no double or triple bonds.! Alkyl Groups A part of a
More informationLook for absorption bands in decreasing order of importance:
1. Match the following to their IR spectra (30 points) Look for absorption bands in decreasing order of importance: a e a 2941 1716 d f b 3333 c b 1466 1.the - absorption(s) between 3100 and 2850 cm-1.
More informationCHEM Chapter 12 Infrared and Mass Spec (homework). Stafford. S18
Exhibit 12-4 The following question(s) refer to the mass spectrum shown below. 1. Refer to Exhibit 12-4. This compound contains C, H, and one other atom. Identify the other atom from the mass spectrum
More informationMOLECULAR REPRESENTATIONS AND INFRARED SPECTROSCOPY
MOLEULAR REPRESENTATIONS AND INFRARED SPETROSOPY A STUDENT SOULD BE ABLE TO: 1. Given a Lewis (dash or dot), condensed, bond-line, or wedge formula of a compound draw the other representations. 2. Give
More information12/27/2010. Chapter 15 Reactions of Aromatic Compounds
Chapter 15 Reactions of Aromatic Compounds Electrophilic Aromatic Substitution Arene (Ar-H) is the generic term for an aromatic hydrocarbon The aryl group (Ar) is derived by removal of a hydrogen atom
More informationChapter 15 Reactions of Aromatic Compounds
Chapter 15 1 Chapter 15 Reactions of Aromatic Compounds Electrophilic Aromatic Substitution Arene (Ar-H) is the generic term for an aromatic hydrocarbon The aryl group (Ar) is derived by removal of a hydrogen
More informationSTRUCTURE ELUCIDATION BY INTEGRATED SPECTROSCOPIC METHODS
Miscellaneous Methods UNIT 14 STRUCTURE ELUCIDATION BY INTEGRATED SPECTROSCOPIC METHODS Structure 14.1 Introduction Objectives 14.2 Molecular Formula and Index of Hydrogen Deficiency 14.3 Structural Information
More informationAP Chemistry Chapter 22 - Organic and Biological Molecules
AP Chemistry Chapter - Organic and Biological Molecules.1 Alkanes: Saturated Hydrocarbons A. Straight-chain Hydrocarbons 1. Straight-chain alkanes have the formula C n H n+. Carbons are sp hybridized The
More informationREACTIONS OF HALOALKANES - SUBSTITUTION AND ELIMINATION
REACTIONS OF HALOALKANES - SUBSTITUTION AND ELIMINATION Haloalkanes (also known as halogenoalkanes and alkyl halides) are organic compounds where one of the hydrogens of an alkane or cycloalkane has been
More informationMCAT Organic Chemistry Problem Drill 10: Aldehydes and Ketones
MCAT rganic Chemistry Problem Drill 10: Aldehydes and Ketones Question No. 1 of 10 Question 1. Which of the following is not a physical property of aldehydes and ketones? Question #01 (A) Hydrogen bonding
More informationMASS Spectrometry. CHAPTER. Introduction: 58 MASS Spectroscopy
58 MASS Spectroscopy APTER 3 MASS Spectrometry Introduction: In the commonly used electron-impact (EI) mode, a mass spectrometer bombards molecules in the vapour phase with a high-energy electron beam
More informationORGANIC SPECTROSCOPY NOTES
- 1 - ORGANIC SPECTROSCOPY NOTES Basics of Spectroscopy UV/vis, IR and NMR are all types of Absorption Spectroscopy, where EM radiation corresponding to exactly the energy of specific excitations in molecules
More informationOrganic Chemistry. FAMILIES of ORGANIC COMPOUNDS
1 SCH4U September 2017 Organic Chemistry Is the chemistry of compounds that contain carbon (except: CO, CO 2, HCN, CO 3 2- ) Carbon is covalently bonded to another carbon, hydrogen and possibly to oxygen,
More informationCHEM 203 Exam 1. Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.
CHEM 203 Exam 1 Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Which of the following elements is a large percentage of both the earth's
More informationAlkanes, Alkenes and Alkynes
Alkanes, Alkenes and Alkynes Hydrocarbons Hydrocarbons generally fall into 2 general groupings, aliphatic hydrocarbons and aromatic hydrocarbons. Aliphatic hydrocarbons contain chains and rings of hydrocarbons,
More informationAn alcohol is a compound obtained by substituting a hydoxyl group ( OH) for an H atom on a carbon atom of a hydrocarbon group.
Derivatives of Hydrocarbons A functional group is a reactive portion of a molecule that undergoes predictable reactions. All other organic compounds can be considered as derivatives of hydrocarbons (i.e.,
More informationClosed book exam, no books, notebooks, notes, etc. allowed. However, calculators, rulers, and molecular model sets are permitted.
Massachusetts Institute of Technology Organic Chemistry 5.13 Friday, September 26, 2003 Prof. Timothy F. Jamison Hour Exam #1 Name (please both print and sign your name) Official Recitation Instructor
More informationCHE1502. Tutorial letter 201/1/2016. General Chemistry 1B. Semester 1. Department of Chemistry CHE1502/201/1/2016
CE1502/201/1/2016 Tutorial letter 201/1/2016 General Chemistry 1B CE1502 Semester 1 Department of Chemistry This tutorial letter contains the answers to the questions in assignment 1. FIRST SEMESTER: KEY
More informationChapter 3. Organic Compounds: Alkanes and Their Stereochemistry
Chapter 3. Organic Compounds: Alkanes and Their Stereochemistry Functional Group: Be able to identify and name any of the functional groups listed on Table 3.1, pages 76-77. Summary of important functional
More informationThe C-X bond gets longerand weakergoing down the periodic table.
Chapter 10: Organohalides Organic molecules containing halogen atoms (X) bonded to carbon are useful compounds in synthesis and on their own. 10.2 Structure of alkyl halides The C-X bond gets longerand
More informationE35 SPECTROSCOPIC TECHNIQUES IN ORGANIC CHEMISTRY
E35 SPECTRSCPIC TECNIQUES IN RGANIC CEMISTRY Introductory Comments. These notes are designed to introduce you to the basic spectroscopic techniques which are used for the determination of the structure
More informationAlkanes and Cycloalkanes
Alkanes and Cycloalkanes Families of Organic Compounds Organic compounds can be grouped into families by their common structural features We shall survey the nature of the compounds in a tour of the families
More information4. Carbon and Its Compounds
4. Carbon and Its Compounds Covalent bonds The bonds formed by the sharing of electrons are known as covalent bonds. In covalent bonding, both the atoms (that are participating in the bonding) share electrons,
More informationORGANIC - BRUICE 8E CH.3 - AN INTRODUCTION TO ORGANIC COMPOUNDS
!! www.clutchprep.com CONCEPT: INDEX OF HYDROGEN DEFICIENCY (STRUCTURAL) A saturated molecule is any molecule that has the maximum number of hydrogens possible for its chemical structure. The rule that
More informationLearning Guide for Chapter 3 - Infrared Spectroscopy
Learning Guide for hapter 3 - Infrared Spectroscopy I. Introduction to spectroscopy - p 1 II. Molecular vibrations - p 3 III. Identifying functional groups - p 6 IV. Interpreting an IR spectrum - p 12
More informationCHEM 203. Midterm Exam 1 October 31, 2008 ANSWERS. This a closed-notes, closed-book exam. You may use your set of molecular models
CEM 203 Midterm Exam 1 ctober 31, 2008 Your name: ANSWERS This a closed-notes, closed-book exam You may use your set of molecular models This exam contains 8 pages Time: 1h 30 min 1. / 15 2. / 16 3. /
More informationDAMIETTA UNIVERSITY. Energy Diagram of One-Step Exothermic Reaction
DAMIETTA UNIVERSITY CHEM-103: BASIC ORGANIC CHEMISTRY LECTURE 5 Dr Ali El-Agamey 1 Energy Diagram of One-Step Exothermic Reaction The vertical axis in this graph represents the potential energy. The transition
More informationCh 22 Carbonyl Alpha ( ) Substitution
Ch 22 Carbonyl Alpha () Substitution The overall reaction replaces an H with an E + The acid-catalyzed reaction has an enol intermediate The base-catalyzed reaction has an enolate intermediate Keto-Enol
More informationInfrared Spectroscopy
Infrared Spectroscopy Introduction Spectroscopy is an analytical technique which helps determine structure. It destroys little or no sample. The amount of light absorbed by the sample is measured as wavelength
More informationChapter 20 (part 2) Organic Chemistry
Chapter 20 (part 2) Organic Chemistry Section 20.7 Alkenes and Alkynes Alkenes: hydrocarbons that contain a carbon carbon double bond. [C n H 2n ] CH 3 CH=CH 2 propene Alkynes: hydrocarbons containing
More information235 Organic II. Final Exam Review REACTIONS OF CONJUGATED DIENES 1,2 VS 1,4 ADDITION REACTIONS OF CONJUGATED DIENES
b. the ompound 7 i 1 Spectral Data: singlet, 196.5 ppm singlet, 14.1 ppm singlet, 14.4 ppm doublet, 19.1 ppm doublet, 18.5 ppm 1 MR Mass Spectrum Absorbance Intensity Infrared Spectrum 65 91 9. Structure:
More informationChapter 15. Reactions of Aromatic Compounds. Electrophilic Aromatic Substitution on Arenes. The first step is the slow, rate-determining step
Electrophilic Aromatic Substitution on Arenes Chapter 15 Reactions of Aromatic Compounds The characteristic reaction of aromatic rings is substitution initiated by an electrophile halogenation nitration
More informationOrganic Chemistry is the chemistry of compounds containing.
Chapter 21 Lecture Notes Organic Chemistry Intro Organic Chemistry is the chemistry of compounds containing. The Bonding of Carbon Because carbon has four valence electrons, it can form covalent bonds.
More informationCHEMISTRY 263 HOME WORK
Lecture Topics: CHEMISTRY 263 HOME WORK Module7: Hydrogenation of Alkenes Hydrogenation - syn and anti- addition - hydrogenation of alkynes - synthesis of cis-alkenes -synthesis of trans-alkenes Text sections:
More information