DOCSLIB.ORG

Reactivity of Iso-Diiodomethane and Iso-Iodoform, Isomers of Ch2i2 and Chi3, Toward the Double Bond of a Variety of Cycloalkenes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Reactivity of Iso-Diiodomethane and Iso-Iodoform, Isomers of Ch2i2 and Chi3, Toward the Double Bond of a Variety of Cycloalkenes Bowling Green State University ScholarWorks@BGSU Chemistry Faculty Publications Chemistry 11-2007 Reactivity Of Iso-diiodomethane And Iso-iodoform, Isomers Of Ch2i2 And Chi3, Toward The Double Bond Of A Variety Of Cycloalkenes Alexander N. Tarnovsky Bowling Green State University, [email protected] Irmin Pascher Torbjorn Pascher Follow this and additional works at: https://scholarworks.bgsu.edu/chem_pub Part of the Chemistry Commons Repository Citation Tarnovsky, Alexander N.; Pascher, Irmin; and Pascher, Torbjorn, "Reactivity Of Iso-diiodomethane And Iso- iodoform, Isomers Of Ch2i2 And Chi3, Toward The Double Bond Of A Variety Of Cycloalkenes" (2007). Chemistry Faculty Publications. 99. https://scholarworks.bgsu.edu/chem_pub/99 This Article is brought to you for free and open access by the Chemistry at ScholarWorks@BGSU. It has been accepted for inclusion in Chemistry Faculty Publications by an authorized administrator of ScholarWorks@BGSU. 11814 J. Phys. Chem. A 2007, 111, 11814-11817 Reactivity of Iso-diiodomethane and Iso-iodoform, Isomers of CH2I2 and CHI3, toward the Double Bond of a Variety of Cycloalkenes Alexander N. Tarnovsky,*,† Irmin Pascher,‡ and Torbjo1rn Pascher*,§ Department of Chemistry and Center for Photochemical Sciences, Bowling Green State UniVersity, Bowling Green, Ohio 43403, Department of Medical Chemistry, UniVersity of Gothenburg, SE-40530 Gothenburg, Sweden, and Department of Chemical Physics, Chemical Center, Lund UniVersity, GetingeVa¨gen 60, SE-22100 Lund, Sweden ReceiVed: May 21, 2007; In Final Form: August 29, 2007 The metastable CH2I-I and CHI2-I isomers formed by UV photolysis of CH2I2 and CHI3 transfer methylene and iodomethylene groups, respectively, to a variety of cycloalkenes, leading to their cyclopropanation. More than a 100-fold increase of the reaction rate with increasing solvent polarity suggests a dipolar transition state. The fastest second-order rates observed were in CH3CN. However, CH2Cl2 will be the more appropriate reaction medium because the isomer thermal stability is greater in CH2Cl2 than in the more polar CH3CN. Introduction SCHEME 1 Photocyclopropanation via ultraviolet irradiation of di- iodomethane (CH2I2) and iodoform (CHI3) in the presence of olefins at room temperature in solution is a reaction of synthetic value,1-4 and it has recently received renewed attention.5 The reaction mechanism and criteria for selection of an optimal set of conditions remain little understood. UV photolysis of CH2I2 in solution has been recently shown to lead to the cleavage of one of the two C-I bonds followed by the efficient primary ‚ ‚ geminate combination of CH2I and I to form the CH2I-I 6-9 isomer (iso-diiodomethane). The decay of CH2I-I follows a mixture of first-order (dissociation back to the radicals, and, in very polar solvent, to ions) and second-order (trapping by ‚ ‚ 7 CH2I and I ) processes, Scheme 1. Upon UV photolysis of CH2I2 in the presence of cyclohexene TABLE 1: Rate Constants (k0) of the First-Order Process - f - f (c6) in solution, CH2I-I was found to react with c6 with CH2I I Products and CHI2 I Products in the 7,10 Alkene-Free Solvents expulsion of I2. This behavior is consistent with the isomer 1-4 -1 serving as the methylene transfer agent. According to IR k0 (s ) - absorption spectra of the CH2I I molecules trapped in frozen solvent CH2I-I CHI2-I matrices, one of the possible resonance forms for this isomer 5 a n-C6H14 (1.8 ( 0.4) × 10 5 c 5 b species is the contact ion pair structure with an electrophilic c-C6H12 (4.1 ( 0.5) × 10 (5.5 ( 0.5) × 10 +- ‚‚‚ - 11,12 5 c 5 c C-atom (H2C I I ). Ab initio MP2 calculations suggest CH2Cl2 (2.2 ( 1.1) × 10 (5.7 ( 0.7) × 10 13 6 a 6 b a noticeable bonding interaction between the two iodine atoms. CH3CN (4.3 ( 0.3) × 10 (4.4 ( 0.7) × 10 Density functional theory (DFT) calculations on isolated (4.2 ( 0.2) × 106 c molecules indicate that the CH2I part of the CH2I-I isomer has a Obtained in ref 7 by extrapolating the measured photolysis energy cationic character and that CH2I-I can react with an olefin dependence of the kobs rate from low to infinitely low energies. See 14 b c (ethylene) in one step to yield cyclopropane and I2. UV also ref 24. Obtained as above, ref 16. The kobs rates and their standard deviations based on repeated measurements at very low photolysis of iodoform (CHI3) in solution leads to similar -1 steps: cleavage of the C-I bond, recombination into the CHI -I photolysis energies (µJ pulse ): 15 (CH2Cl2), 35 (CH3CN) for CHI3, 2 and 3.5 (CH Cl ), 35 (c-C H ) for CH I , this work. isomer (iso-iodoform), and cage escape of the geminate radical 2 2 6 12 2 2 17 pair.15,16 Also, there is evidence for considerable radical trapping amounts of iodocyclopropanated products, in addition to I2. 16 - ‚ of the CHI2-I intermediate. Previous photochemical synthetic Both CHI2 I and the CHI2 radical were proposed to be 5,18 studies reported that UV irradiation of CHI3 in the presence of iodomethylene transfer agents. c6 and several linear alkenes produces synthetically useful In the present work, we wish to report transient spectroscopic studies of the photocyclopropanation reaction between the * Corresponding authors. A.N.T.: Phone, (419) 374-3865; fax, (419) CH2I-I isomer of CH2I2 and several cycloalkenes, specifically 372-9809; e-mail, [email protected]. T.P.: Phone, 46-46-222-4739; fax, cyclopentene (c5), cycloheptene (c7), 1-methylcyclohexene (Me- 46-46-222-4119; e-mail, [email protected]. c6), and 1,2-dimethylcyclohexene (diMe-c6). A similar study † Bowling Green State University. ‡ University of Gothenburg. was conducted of the photocyclopropanation reaction between § Lund University. the CHI2-I isomer of CHI3 and c6. 10.1021/jp073917u CCC: $37.00 © 2007 American Chemical Society Published on Web 10/27/2007 Reactivity of Iso-diiodomethane and Iso-iodoform J. Phys. Chem. A, Vol. 111, No. 46, 2007 11815 order photocyclopropanation rate constant. The kobs rates are approximated as kobs ) k0 + kt × [radicals, isomer], where kt is the total trapping rate constant. Results and Discussion The CH2I-I isomer intermediate is produced by means of 310 nm nanosecond photolysis of CH2I2 in deoxygenated cyclohexane, dichloromethane, and acetonitrile. The CHI2-I isomer is formed from CHI3 in the same way. Under low excitation conditions, the decay rate constant (kobs) of both the 6 CH2I-I and the CHI2-I isomers is observed to be in the 10 - 7 -1 10 s range, with little I2 formed directly. The true first-order rate constants (k0) of the decay of CH2I-I and CHI2-I in neat solvents can be obtained by extrapolating the isomer decay rates measured under low excitation conditions to infinitely low power Figure 1. The pseudo first-order k - decay rates (symbols) of obs olefin that corresponds to the rate in the absence of trapping, Table 1. the CH2I-I isomer plotted against cycloheptene (c7) content for the -1 photolyzed (0.04 mJ pulse ) samples of CH2I2 (1 mM) in the The k0 rates are 10 times faster in CH3CN than in the less polar deoxygenated solvents cyclohexane (9), dichloromethane (O), and c-C6H12 and CH2Cl2, because of the opening of the ionic decay acetonitrile (3). The slope of the linear fit (lines) gives the second- channel.7 order kq rate constants summarized in Table 2. As seen in the inset, - - The decay of the CH2I I isomer is accelerated by the addition the 390 nm absorption band of the CH2I I isomer in CH2Cl2 solution of increasing concentrations of cycloalkenes in all three solvents, decays as a single exponential with the corresponding decay rate Figure 1. The absorption rise of I2 at low alkene concentrations constant kobs-olefin in the presence of excess c7. The cycloalkene 20 concentration (M) in the photolyzed solution is shown beside each decay and alkene:I2 charge-transfer complexes (probe wavelength, curve. 320 nm) at high alkene concentrations occurs with rate constants similar to those of the CH2I-I isomer decay. This behavior is consistent with cyclopropanation of the alkene CdC bond by SCHEME 2 CH2I-I, Scheme 1. Generally, as the polarity of the solvent increases on going from c-C6H12 to CH2Cl2, the cyclopropa- nation rate (kq) increases by a factor of 100, and going from CH2Cl2 to CH3CN increases the kq by a factor of ∼1.5, Table 2. This is consistent with a photocyclopropanation mechanism involving a highly dipolar activated complex, as shown sche- Experimental Section matically in Scheme 2. This transition complex can be drawn either as the open carbocationic structure with a single bond In our setup,19 the 310 nm photolysis pulse (∼8 ns fwhm) between the carbenic carbon and one alkene carbon or as the was produced by frequency doubling the 620 nm output from closed carbocation with partial bonding between the carbenic an OPO pumped by the 355 nm output from the Nd:YAG laser. carbon and both alkene carbon atoms. The latter probably occurs The photolysis pulse typically delivered 3.5-70 µJintoa2mm based on the observed stereospecificity for the photocyclopro- 3,17 diameter spot at the sample. The CH2I2 (1 mM) and CHI3 (1 panation reactions involving simple alkenes. mM) samples (20 ( 1 °C) were deoxygenated and sealed in a The effect of the ring size is modest, Table 2. The reaction 1 cm cuvette equipped with a magnetic stirrer. CH2I2 and CHI3 rate for c5 is about one-half of the rate for c6 and c7, with the (both from Fluka, >98%), solvents (Merck, p.a.), c6 (Aldrich, corresponding relative rates averaged over the solvents being 99+%), c5 (Fluka, g98.5%), c7 (Aldrich, 97%), Me-c6 (Fluka, 0.51, 1.0, and 0.94.
Load more

Recommended publications
  • Chemistry (55)
    156 Chemistry (55) Introduction 3) To expose the students to various emerging According to NCF 2005, the new and new areas of chemistry and apprise them updated curriculum is introduced at +2 stage. with their relevance in their future studies There is a need to provide the sufficient and their applications in various spheres conceptual background of chemistry which will of chemical sciences and technology. help the students to appear for different common 4) To equip students to face various changes entrance test at the state level and the national related to health, nutrition, environment, level. This new syllabus will make them population, weather, industries and competent to meet the challenges of academic agriculture. and professional courses like medicine, 5) To develop problem solving skills in engineering, technology, etc, after the +2 stage. students. The syllabus is comparable to the international 6) To expose the students to different level. processes used in industries and their The syllabus contains areas like physical, technological applications. organic, inorganic, industrial, analytical and 7) To apprise students with interface of polymer chemistry. The upgraded syllabus has chemistry with other disciplines of science taken care of new formulations and such as physics, biology, geology, nomenclature of elements, compounds and engineering, etc. IUPAC units of physical quantities. New nomenclature, symbols and formulations, Std. XI (Theory) fundamental concepts, modern techniques are given importance. Unit 1: Some Basic Concepts of Chemistry Objectives : General Introduction: Importance and The broad objectives of teaching scope of chemistry. Historical approach to Chemistry at Higher Secondary stage are to particulate nature of matter, laws of help the learners : chemical combination, Dalton’s atomic 1) To promote understanding of basic facts theory : concept of elements, atoms and and concepts in chemistry while retaining molecules.
    [Show full text]
  • Download Download
    Test for Acetone in Urine 189 AN IMPROVED TEST FOR ACETONE IN URINE. R. E. Lyons and J. T. Brundage, Indiana University. Lieben's test for acetone 1 depends upon the formation of iodoform when potassium iodide, iodine solution, and a few drops of sodium hydroxide solution are added to an acetone containing mixture. The iodoform is recognized by its distinctive odor and, microscopically, by the 1 star, or hexagonal crystals. The test is not specific since both ethyl alcohol and acetic aldehyde also react with these reagents to yield iodo- form. This sometimes leads to erroneous results because of alcohol formed through sugar fermentation in diabetic urine. The difficulty is obviated" by substituting ammonium hydroxide for the caustic alkali as proposed by Gunning'5 in a modification of the Lieben Test. In either test the reaction is much more sensitive if a urine dis- tillate is used. The distillation not only frees the acetone from non- volatile interfering substances, but converts some acetonacetic (di-acetic) 4 acid, if present, into acetone. Protein interferes and, if present, the separation of acetone by distillation or aeration is necessary. M. KohlthofF' states that 100 mg. each of potassium iodide and chlor- amine T, 10-20 drops of 4N ammonium hydroxide and 10 cc. of a solu- tion of one part acetone in 10,000 parts of 2 per cent ethyl alcohol when warmed to 60 °C. gave an iodoform precipitate in two hours. The object of our investigation has been to determine (a) whether this reaction could be applied as a specific test for acetone in urine, (b) what urinary constituents or preservatives interfere, (c) if the necessity of distillation, or aeration, of the urine could be dispensed with, and (d) the conditions for attaining the maximum sensitiveness of the reaction.
    [Show full text]
  • United States Patent (19) (11) 4,161,571 Yasui Et Al
    United States Patent (19) (11) 4,161,571 Yasui et al. 45 Jul. 17, 1979 (54) PROCESS FOR PRODUCTION OF THE 4,080,493 3/1978 Yasui et al. .......................... 260/879 MALE CANHYDRDE ADDUCT OF A 4,082,817 4/1978 Imaizumi et al. ...................... 526/46 LIQUID POLYMER 4,091,198 5/1978 Smith ..................................... 526/56 75 Inventors: Seimei Yasui, Takarazuka; Takao FOREIGN PATENT DOCUMENTS Oshima, Sonehigashi, both of Japan 2262677 2/1975 France ....................................... 526/56 73) Assignee: Sumitomo Chemical Company, 44-1989 1/1969 Japan ......................................... 526/56 Limited, Osaka, Japan Primary Examiner-William F. Hamrock Attorney, Agent, or Firm-Birch, Stewart, Kolasch and 21 Appl. No.: 843,311 Birch 22 Filed: Oct. 18, 1977 57 ABSTRACT Related U.S. Application Data A process for production of the maleic anhydride ad duct of a liquid polymer having a maleic anhydride 62 Division of Ser. No. 733,914, Oct. 19, 1976, Pat, No. addition amount of 2 to 70% by weight, which com 4,080,493. prises reacting a liquid polymer having a molecular 51 Int. C.’................................................ CO8F 8/46 weight of 150 to 5,000 and a viscosity of 2 to 50,000 cp (52) U.S. C. ...................................... 526/90; 526/192; at 30 C. in the presence of at least one compound, as a 526/209; 526/213; 526/193; 526/195; 526/226; gelation inhibitor, selected from the group consisting of 526/233; 526/237; 526/238; 526/272; 525/285; imidazoles, thiazoles, metallic salts of mercapto 525/249; 525/251; 525/255; 525/245; 525/248 thiazoles, urea derivatives, naphthylamines, nitrosa (58) Field of Search ................
    [Show full text]
  • Laboratory 23: Properties of Aldehydes and Ketones
    Laboratory 23: Properties of Aldehydes and Ketones Introduction Aldehydes and Ketones represent an important class of organic molecules containing a carbonyl carbon. In this experiment you will study the chemical properties of aldehydes and ketones. Solubility in water, and organic solvents, combustibility, and reactivity with various chemical reagents will be examined. Discussion Structure of Aldehydes and Ketones Aldehydes and Ketones are organic compounds containing a carbonyl carbon (R−C−O−R') (Figure 1 below) functional group. Carboxylic Acids and Esters also contain a carbonyl carbon, and will be explored in a future experiment. The carbonyl carbon is a polar group with the carbon having a slight excess of positive charge and the oxygen atom having a slight excess of negative charge. Chemical Properties Aldehydes and ketones are created by the mild oxidation of primary and secondary alcohols. One such method to oxidize alcohols is with copper (II) oxide. Upon heading, copper wire (Cu0) in an open flame leads to the formation of copper (II) oxide. The copper (II) oxide is then reacted with an alcohol to form an aldehyde or ketone, copper (I) oxide and water. [O] Primary Alcohol −−! Aldehyde [O] Secondary Alcohol −−! Ketone Chemically aldehydes and ketones both contain a carbonyl carbon and thus have similar chemical reactivities. However, aldehydes are more susceptible to oxidation because of the hydrogen atom attached to the carbonyl group. This is the basis for distinguishing between these two classes of compounds. Several tests are useful for differentiating between aldehydes and ketones. The first test is referred to as the Tollens' or Silver Mirror test.
    [Show full text]
  • Synthesis of Trialkyl 2-Halogeno-1,1,1-Ethanetricarboxylates
    General Papers ARKIVOC 2016 (iv) 352-362 Synthesis of trialkyl 2-halogeno-1,1,1-ethanetricarboxylates Juan Zinczuk* and Gustavo A. Carnavale Instituto de Química Rosario (CONICET-UNR . Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario. Suipacha 531- 2000 Rosario - Argentina E-mail: [email protected] DOI: http://dx.doi.org/10.3998/ark.5550190.p009.567 Abstract A series of trialkyl 2-halogeno-1,1,1-ethanetricarboxylates (Hal = Cl, Br, I) was obtained in high yields by halomethylenation of trialkyl methanetricarboxylates that in turn were derived from dialkyl malonates. The variables that control the reaction (solvent, temperature, time of reaction, base, and alkylating agent) were adjusted to optimize the yield. This new family of compounds may be considered as synthetic equivalents of the unstable dialkyl (halomethyl)malonates. Keywords: Halomethylenation, dialkyl (halomethyl)malonates, trialkyl 2-halogeno-1,1,1- ethanetricarboxylates, optimized synthesis. Introduction We are interested in the reactivity of metallic homoenolates, formally derived from dialky methylmalonates, and proposed the metallation of the appropriate dialkyl (halomethyl)malonates as a method of preparation. Dialkyl (halomethyl)malonates are scarcely referenced in the literature. The only reported example corresponds to diethyl (bromomethyl)malonate, obtained in impure form by Simonsen by reaction of diethyl (2-methoxymethyl)malonate and hydrobromic acid.1 More recently Dowd and Shapiro improved the compound purity but recognized the sensible nature of the bromo compound.2 The study of the halomethylenation of dialkylmalonates began more than a century. The reaction of diethyl malonate (1) and diiodomethane in the presence of sodium ethoxide was first reported by Guthzeit and Dressel in 1888.3,4 They used a half equivalent of diiodomethane and obtained 84% of tetraethyl 1,1,3,3-propanetetracarboxylate (2).
    [Show full text]
  • Pharmaceutical Services Division and the Clinical Research Centre Ministry of Health Malaysia
    A publication of the PHARMACEUTICAL SERVICES DIVISION AND THE CLINICAL RESEARCH CENTRE MINISTRY OF HEALTH MALAYSIA MALAYSIAN STATISTICS ON MEDICINES 2008 Edited by: Lian L.M., Kamarudin A., Siti Fauziah A., Nik Nor Aklima N.O., Norazida A.R. With contributions from: Hafizh A.A., Lim J.Y., Hoo L.P., Faridah Aryani M.Y., Sheamini S., Rosliza L., Fatimah A.R., Nour Hanah O., Rosaida M.S., Muhammad Radzi A.H., Raman M., Tee H.P., Ooi B.P., Shamsiah S., Tan H.P.M., Jayaram M., Masni M., Sri Wahyu T., Muhammad Yazid J., Norafidah I., Nurkhodrulnada M.L., Letchumanan G.R.R., Mastura I., Yong S.L., Mohamed Noor R., Daphne G., Kamarudin A., Chang K.M., Goh A.S., Sinari S., Bee P.C., Lim Y.S., Wong S.P., Chang K.M., Goh A.S., Sinari S., Bee P.C., Lim Y.S., Wong S.P., Omar I., Zoriah A., Fong Y.Y.A., Nusaibah A.R., Feisul Idzwan M., Ghazali A.K., Hooi L.S., Khoo E.M., Sunita B., Nurul Suhaida B.,Wan Azman W.A., Liew H.B., Kong S.H., Haarathi C., Nirmala J., Sim K.H., Azura M.A., Asmah J., Chan L.C., Choon S.E., Chang S.Y., Roshidah B., Ravindran J., Nik Mohd Nasri N.I., Ghazali I., Wan Abu Bakar Y., Wan Hamilton W.H., Ravichandran J., Zaridah S., Wan Zahanim W.Y., Kannappan P., Intan Shafina S., Tan A.L., Rohan Malek J., Selvalingam S., Lei C.M.C., Ching S.L., Zanariah H., Lim P.C., Hong Y.H.J., Tan T.B.A., Sim L.H.B, Long K.N., Sameerah S.A.R., Lai M.L.J., Rahela A.K., Azura D., Ibtisam M.N., Voon F.K., Nor Saleha I.T., Tajunisah M.E., Wan Nazuha W.R., Wong H.S., Rosnawati Y., Ong S.G., Syazzana D., Puteri Juanita Z., Mohd.
    [Show full text]
  • University Miaorilms International 300 N
    INFORMATION TO USERS This reproduction was made from a copy of a document sent to us for microfilming. While the most advanced technology has been used to photograph and reproduce this document, the quality of the reproduction is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help clarify markings or notations which may appear on this reproduction. 1. The sign or “target” for pages apparently lacking from the document photographed is “Missing Page(s)”. If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure complete continuity. 2. When an image on the film is obliterated with a round black mark, it is an indication of either blurred copy because of movement during exposure, duplicate copy, or copyrighted materials that should not have been filmed. For blurred pages, a good image of the page can be found in the adjacent frame. If copyrighted materials were deleted, a target note will appear listing the pages in the adjacent frame. 3. When a map, drawing or chart, etc., is part of the material being photographed, a definite method of “sectioning” the material has been followed. It is customary to begin filming at the upper left hand comer of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again—beginning below the first row and continuing on until complete.
    [Show full text]
  • Safety Data Sheet Iodoform Compound Paint
    SAFETY DATA SHEET IODOFORM COMPOUND PAINT 1. IDENTIFICATION OF THE SUBSTANCE/PREPARATION AND THE COM PANY: PRODUCT NAME: IODOFORM COMPOUND PAINT PART No.: M028 SUPPLIER: J M Loveridge plc Southbrook Road, Southampton Hampshire SO15 1BH Tel: 023 8022 2008 Fax: 023 8022 2117 2. COMPOSITION/INFORMATION ON INGREDIENTS: NAME CONTENT CAS No.: EINECS Nr.: CLASSIFICATION DIETHYL ETHER 60-100 % 60-29-7 200-467-2 Xn ,Fx R-12, 19, 22, 66, 67 IODOFORM 10-30 % 75-47-8 200-874-5 Xn R-20/21/22, 36 The Full Text for all R-Phrases are Displayed in Section 16 3. HAZARDS IDENTIFICATION: Extremely flammable. Harmful if swallowed. Repeated exposure may cause skin dryness or cracking. Vapours may cause drowsiness and dizziness. 4. FIRST AID MEASURES: GENERAL: IN ALL CASES OF DOUBT OR WHEN SYMPTOMS PERSIST, ALWAYS SEEK MEDICAL ATTENTION IN H A LA T IO N : Move affected person from exposure. If recovery not rapid or complete seek medical attention. If breathing stops, provide artificial respiration. Keep affected person warm and at rest. IN G E ST IO N: DO NOT INDUCE VOMITING. In case of spontaneous vomiting, be sure that vomit can freely drain because of danger of suffocation. Only when conscious, rinse mouth with plenty of water and give plenty of water to drink - (approx 500ml). Keep patient at rest and obtain medical attention. SKIN: Remove contaminated clothing. Wash affected area with plenty of soap and water. If 1/5 10178 - IODOFORM COMPOUND PAINT symptoms occur or persist, obtain medical attention. Launder clothing before re-use. EYES: Rinse immediately with plenty of water for at least 5 minutes while lifting the eye lids.
    [Show full text]
  • Haloform Reaction - Wikipedia
    6/13/2020 Haloform reaction - Wikipedia Haloform reaction The haloform reaction is a chemical reaction where a haloform Haloform reaction (CHX , where X is a halogen) is produced by the exhaustive 3 Named after Adolf Lieben halogenation of a methyl ketone (RCOCH3, where R can be either a hydrogen atom, an alkyl or an aryl group), in the presence of a Reaction type Substitution base.[1][2][3] The reaction can be used to transform acetyl groups into reaction carboxyl groups or to produce chloroform (CHCl3), bromoform Identifiers (CHBr3), or iodoform (CHI3) and also cyanide. Organic haloform-reaction Chemistry Portal Contents Mechanism Scope Applications Laboratory scale Industrially As a by-product of water chlorination History References Mechanism In the first step, the halogen disproportionates in the presence of hydroxide to give the halide and hypohalite (example with bromine, but reaction is the same in case of chlorine and iodine; one should only substitute Br for Cl or I): If a secondary alcohol is present, it is oxidized to a ketone by the hypohalite: If a methyl ketone is present, it reacts with the hypohalite in a three-step process: 1. Under basic conditions, the ketone undergoes keto-enol tautomerization. The enolate undergoes electrophilic attack by the hypohalite (containing a halogen with a formal +1 charge). https://en.wikipedia.org/wiki/Haloform_reaction#Iodoform_reaction 1/5 6/13/2020 Haloform reaction - Wikipedia 2. When the α(alpha) position has been exhaustively halogenated, the molecule undergoes a nucleophilic − acyl substitution by hydroxide, with CX3 being the leaving group stabilized by three electron- − withdrawing groups.
    [Show full text]
  • Iodoform Packing
    Created by the British Columbia Provincial Nursing Skin and Wound Committee in collaboration with the Wound Clinicians from / Skin and Wound Product Information Sheet Iodoform Packing Classification Antimicrobial/Antiseptic: Iodine Key Points A ravel-resistant strip gauze packing impregnant with Iodoform, an antiseptic effective against pseudomonas. In the presence of exudate, iodoform breaks down to release Iodine (96%) and therefore should be used with caution. The packing’s colour may be opaque to yellowish and may have an oily appearance, as a small amount of oil may have been use to aid in easier removal of product from the container. Should be packed dry. Indications Use under the direction of a Physician, NP, NSWOC/Wound Clinician: o For wounds with or without undermining, sinus tract/tunnels which have signs and symptoms (S&S) of, or are at risk for, local wound infection. Precautions May cause some discomfort/pain, especially when first applied. Avoid using before and after radio-iodine diagnostic tests Make Physician/NP aware of Iodine usage for clients: o Taking lithium, as Iodine may increase the possibility of hypothyroidism when used in combination with lithium. Blood work should be monitored on a regular basis. o With renal impairment, as poor renal function is thought to be a factor in increased iodine levels in serum and urine with prolonged use and use in large wounds. o With thyroid disorders, as they are more susceptible to thyroid metabolism changes in long-term therapy. Thyroid function should be monitored if large areas are being treated for a prolonged period of time.
    [Show full text]
  • Jamaludin Al Anshori, M.Sc. Laboratory of Organic Chemistry
    LABORATORY MANUAL OF EXPERIMENTAL ORGANIC CHEMISTRY I Compiled By: Jamaludin Al Anshori, M.Sc. Laboratory of Organic Chemistry Faculty of Mathematics and Natural Sciences Universitas Padjadjaran 2008 LABORATORY MANUAL OF EXPERIMENTAL ORGANIC CHEMISTRY I Compiled by: Jamaludin Al Anshori, M.Sc. LABORATORY OF ORGANIC CHEMISTRY FACULTY OF MATHEMATICS AND NATURAL SCIENCES UNIVERSITAS PADJADJARAN JATINANGOR JATINANGOR, AUGUST 21, 2008 Approved by: Compiler: Head of Organic Chemistry Laboratory Tati Herlina, M.Si. Jamaludin Al Anshori, M.Sc. NIP. 131 772 457 NIP. 132 306 074 i TABLE OF CONTENTS Table of Contents ....................................................................................................................i Preface ................................................................................................................................ iv A. Laboratory’s Rules………………………………………………………………………… v B. Introduction to The Laboratory……………………………………………………………vii Laboratory Techniques : Experiment 1 I.1 Extraction........................................................................................................................1 I.1.1 Introduction........................................................................................................... 1 I.1.2 Using the separating funnel.................................................................................. 2 I.1.3 Procedure ............................................................................................................. 3 I.1.4 Question ..............................................................................................................
    [Show full text]
  • MI-GEE Brand Methylene Iodide
    CHEMICAL BASED LIQUIDS BULLETIN NO.32 Chemical Based Products GEOLIQUIDS MI-GEE Brand Methylene Iodide MI-GEE is a pure form of Methylene Iodide and is widely moisture. Use in or exposure to strong sunlight or strong used for testing and separating minerals and for testing mercury vapor lights should be avoided. Any darkening is high index glasses, minerals and gems. It is also used in a due to liberation of a small amount of free iodine. This is variety of organic chemical syntheses. One of these is the easily removed by shaking with a cool 5 - 10% solution of Simmons & Smith Synthesis (JACS 80, 5323, 1958) for Sodium Hydroxide or Sodium Carbonate, washing twice with putting a methylene group into an organic molecule. plain water, separating and filtering. Due to the highly labile nature of Methylene Iodide, Gas Chromatography can not be Properties: used to analyze it, as heat decomposes the material to give low results. MI-GEE is shipped with Copper wire screen pre- MI-GEE Assays 99.9% Minimum CH2I2 servative added. Copper wire sinks to the bottom, causes Formula Weight: 267:87 no difficulty in use, does not contaminate MI-GEE, and will keep it light in color for several years. MI-GEE should always Synonym: Diiodomethane be stored in total darkness and in closed containers when Iodine Content, Theory: 94.76% not in use. Mercury should never be used to lighten the color or preserve Methylene Iodide as it produces toxic Density: d2 0= 3.325 (Very close to Specific Gravity) 4 compounds. 15 Refractive Index: n D = 1.74 Melting Point: 5-6°C (4l - 42.8°F) MI-GEE Is miscible with acetone, methanol, ethanol, methy- lene chloride, ether, chloroform, dimethyl sulfoxide and Boiling Point: 181°C (358ºF) other solvents.
    [Show full text]