Thioacetone is an organosulfur compound belonging to the -thione group called thioketones, with a chemical formula (CH3)2CS. It is an unstable orange or brown substance that can be isolated only at low temperatures.[3] Above −20 °C (−4 °F), thioacetone readily converts to a polymer and a trimer, trithioacetone.[4] It has an extremely potent, unpleasant odor, and is considered one of the worst-smelling chemicals known to man.[citation needed]
Thioacetone is usually obtained by cracking the cyclic trimertrithioacetone, [(CH3)2CS]3. The trimer is prepared by pyrolysis of allyl isopropyl sulfide or by treating acetone with hydrogen sulfide in the presence of a Lewis acid.[5][6] The trimer cracks at 500–600 °C (932–1,112 °F) to give the thione.[3][7][2]
Polymerization
Unlike its oxygen analogue acetone, which does not polymerise easily, thioacetone spontaneously polymerizes even at very low temperatures, pure or dissolved in ether or ethylene oxide, yielding a white solid that is a varying mixture of a linear polymer ···–[C(CH 3) 2–S–] n–··· and the cyclic trimer trithioacetone. Infrared absorption of this product occurs mainly at 2950, 2900, 1440, 1150, 1360, and 1375 cm−1 due to the geminal methyl pairs, and at 1085 and 643 cm−1 due to the C–S bond. The 1H NMR spectra shows a single peak at x = 8.1.[2]
The mean molecular weight of the polymer varies from 2000 to 14000 depending on the preparation method, temperature, and presence of the thioenoltautomer. The polymer melts in the range of about 70 °C to 125 °C. Polymerization is promoted by free radicals and light.[2]
The cyclic trimer of thioacetone (trithioacetone) is a white or colorless compound with a melting point of 24 °C (75 °F), near room temperature. It also has a disagreeable odor.[4]
Odor
Thioacetone has an intensely foul odour. Like many low molecular weight organosulfur compounds, the smell is potent and can be detected even when highly diluted.[8] In 1889, an attempt to distill the chemical in the German city of Freiburg was followed by cases of vomiting, nausea and unconsciousness in an area with a radius of 0.75 kilometres (0.47 mi) around the laboratory due to the smell.[9] In an 1890 report, British chemists at the Whitehall Soap Works in Leeds noted that dilution seemed to make the smell worse and described the smell as "fearful".[10] In 1967, Esso researchers repeated the experiment of cracking trithioacetone, at a laboratory south of Oxford, UK. They reported their experience as follows:
Recently we found ourselves with an odour problem beyond our worst expectations. During early experiments, a stopper jumped from a bottle of residues, and, although replaced at once, resulted in an immediate complaint of nausea and sickness from colleagues working in a building two hundred yards [180 m] away. Two of our chemists who had done no more than investigate the cracking of minute amounts of trithioacetone found themselves the object of hostile stares in a restaurant and suffered the humiliation of having a waitress spray the area around them with a deodorant. The odours defied the expected effects of dilution since workers in the laboratory did not find the odours intolerable... and genuinely denied responsibility since they were working in closed systems. To convince them otherwise, they were dispersed with other observers around the laboratory, at distances up to a quarter of a mile [0.40 km], and one drop of either acetone gem-dithiol or the mother liquors from crude trithioacetone crystallisations were placed on a watch glass in a fume cupboard. The odour was detected downwind in seconds.[8]
Thioacetone is sometimes considered a dangerous chemical due to its extremely foul odor and its supposed ability to render people unconscious, induce vomiting, and be detected over long distances. However, modern-day tests suggest that these risks could be somewhat exaggerated. As of 2023, at least two YouTube personalities (Nigel of "NileRed"[11] and Zach of "LabCoatz"[12]) have published videos showing themselves smelling freshly-prepared thioacetone, both up-close and from a distance. In both cases, the individuals simply described the smell as "sulfurous", with none of the side effects (nausea, vomiting, or unconsciousness) being observed.
^ abcdefWilliam H. Sharkey (1979): "Polymerization through the carbon-sulfur double bond". Polymerization, series Advances in Polymer Science, volume 17, pages 73–103. doi:10.1007/3-540-07111-3_2
^ abR.D. Lipscomb; W.H. Sharkey (1970). "Characterization and polymerization of thioacetone". Journal of Polymer Science Part A: Polymer Chemistry. 8 (8): 2187–2196. Bibcode:1970JPoSA...8.2187L. doi:10.1002/pol.1970.150080826.
^Bailey, William J.; Chu, Hilda (1965). "Synthesis of polythioacetone". ACS Polymer Preprints. 6: 145–155.
^Bohme, Horst; Pfeifer, Hans; Schneider, Erich (1942). "Dimeric thioketones". Berichte der Deutschen Chemischen Gesellschaft. 75B (7): 900–909. doi:10.1002/cber.19420750722. Note: This early report mistakes the trimer for the monomer
^Kroto, H.W.; Landsberg, B.M.; Suffolk, R.J.; Vodden, A. (1974). "The photoelectron and microwave spectra of the unstable species thioacetaldehyde, CH3CHS, and thioacetone, (CH3)2CS". Chemical Physics Letters. 29 (2): 265–269. Bibcode:1974CPL....29..265K. doi:10.1016/0009-2614(74)85029-3. ISSN 0009-2614.
^ abDerek Lowe (June 11, 2009). "Things I Won't Work With: Thioacetone". In The Pipeline.
^E. Baumann & E. Fromm (1889). "Ueber Thioderivate der Ketone". Berichte der Deutschen Chemischen Gesellschaft. 22 (2): 2592–2599. doi:10.1002/cber.188902202151.
^Chemical News and Journal of Industrial Science. Chemical news office. 1890. p. 219.
thioacetone, organosulfur, compound, belonging, thione, group, called, thioketones, with, chemical, formula, unstable, orange, brown, substance, that, isolated, only, temperatures, above, thioacetone, readily, converts, polymer, trimer, trithioacetone, extreme. Thioacetone is an organosulfur compound belonging to the thione group called thioketones with a chemical formula CH3 2CS It is an unstable orange or brown substance that can be isolated only at low temperatures 3 Above 20 C 4 F thioacetone readily converts to a polymer and a trimer trithioacetone 4 It has an extremely potent unpleasant odor and is considered one of the worst smelling chemicals known to man citation needed Thioacetone NamesPreferred IUPAC name Propane 2 thione 1 Systematic IUPAC name Thiopropan 2 oneOther names Propanethione Thiopropanone Thioacetone Dimethyl thioketone Sulfocarbon dimethanide Dimethyl methylene sulfide Sulfoacetone SulfopropanoneIdentifiersCAS Number 4756 05 2 monomer828 26 2 trimer3D model JSmol Interactive imageChemSpider 557043PubChem CID 641811CompTox Dashboard EPA DTXSID70963875InChI InChI 1S C3H6S c1 3 2 4 h1 2H3Key JTNXQVCPQMQLHK UHFFFAOYSA NInChI 1 C3H6S c1 3 2 4 h1 2H3Key JTNXQVCPQMQLHK UHFFFAOYATSMILES CC S CPropertiesChemical formula C 3H 6SMolar mass 74 14 g mol 1Appearance Orange to brown liquidOdor Putrid and intensely foulMelting point 55 C 218 15k 67 F 2 Boiling point 70 C 343 15k 158 F 2 HazardsOccupational safety and health OHS OSH Main hazards Odor skin irritantExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Infobox references Thioacetone was first obtained in 1889 by Baumann and Fromm as a minor impurity in their synthesis of trithioacetone 2 Contents 1 Preparation 2 Polymerization 3 Odor 4 See also 5 References 6 External linksPreparation EditThioacetone is usually obtained by cracking the cyclic trimer trithioacetone CH3 2CS 3 The trimer is prepared by pyrolysis of allyl isopropyl sulfide or by treating acetone with hydrogen sulfide in the presence of a Lewis acid 5 6 The trimer cracks at 500 600 C 932 1 112 F to give the thione 3 7 2 Polymerization EditUnlike its oxygen analogue acetone which does not polymerise easily thioacetone spontaneously polymerizes even at very low temperatures pure or dissolved in ether or ethylene oxide yielding a white solid that is a varying mixture of a linear polymer C CH3 2 S n and the cyclic trimer trithioacetone Infrared absorption of this product occurs mainly at 2950 2900 1440 1150 1360 and 1375 cm 1 due to the geminal methyl pairs and at 1085 and 643 cm 1 due to the C S bond The 1H NMR spectra shows a single peak at x 8 1 2 The mean molecular weight of the polymer varies from 2000 to 14000 depending on the preparation method temperature and presence of the thioenol tautomer The polymer melts in the range of about 70 C to 125 C Polymerization is promoted by free radicals and light 2 The cyclic trimer of thioacetone trithioacetone is a white or colorless compound with a melting point of 24 C 75 F near room temperature It also has a disagreeable odor 4 Odor EditThioacetone has an intensely foul odour Like many low molecular weight organosulfur compounds the smell is potent and can be detected even when highly diluted 8 In 1889 an attempt to distill the chemical in the German city of Freiburg was followed by cases of vomiting nausea and unconsciousness in an area with a radius of 0 75 kilometres 0 47 mi around the laboratory due to the smell 9 In an 1890 report British chemists at the Whitehall Soap Works in Leeds noted that dilution seemed to make the smell worse and described the smell as fearful 10 In 1967 Esso researchers repeated the experiment of cracking trithioacetone at a laboratory south of Oxford UK They reported their experience as follows Recently we found ourselves with an odour problem beyond our worst expectations During early experiments a stopper jumped from a bottle of residues and although replaced at once resulted in an immediate complaint of nausea and sickness from colleagues working in a building two hundred yards 180 m away Two of our chemists who had done no more than investigate the cracking of minute amounts of trithioacetone found themselves the object of hostile stares in a restaurant and suffered the humiliation of having a waitress spray the area around them with a deodorant The odours defied the expected effects of dilution since workers in the laboratory did not find the odours intolerable and genuinely denied responsibility since they were working in closed systems To convince them otherwise they were dispersed with other observers around the laboratory at distances up to a quarter of a mile 0 40 km and one drop of either acetone gem dithiol or the mother liquors from crude trithioacetone crystallisations were placed on a watch glass in a fume cupboard The odour was detected downwind in seconds 8 Thioacetone is sometimes considered a dangerous chemical due to its extremely foul odor and its supposed ability to render people unconscious induce vomiting and be detected over long distances However modern day tests suggest that these risks could be somewhat exaggerated As of 2023 at least two YouTube personalities Nigel of NileRed 11 and Zach of LabCoatz 12 have published videos showing themselves smelling freshly prepared thioacetone both up close and from a distance In both cases the individuals simply described the smell as sulfurous with none of the side effects nausea vomiting or unconsciousness being observed See also EditThiobenzophenone a thioketone that can be isolated as a solid Bromoacetone Chloroacetone Fluoroacetone IodoacetoneReferences Edit International Union of Pure and Applied Chemistry 2014 Nomenclature of Organic Chemistry IUPAC Recommendations and Preferred Names 2013 The Royal Society of Chemistry p 739 doi 10 1039 9781849733069 ISBN 978 0 85404 182 4 a b c d e f William H Sharkey 1979 Polymerization through the carbon sulfur double bond Polymerization series Advances in Polymer Science volume 17 pages 73 103 doi 10 1007 3 540 07111 3 2 a b V C E Burnop K G Latham 1967 Polythioacetone Polymer Polymer 8 589 607 doi 10 1016 0032 3861 67 90069 9 a b R D Lipscomb W H Sharkey 1970 Characterization and polymerization of thioacetone Journal of Polymer Science Part A Polymer Chemistry 8 8 2187 2196 Bibcode 1970JPoSA 8 2187L doi 10 1002 pol 1970 150080826 Bailey William J Chu Hilda 1965 Synthesis of polythioacetone ACS Polymer Preprints 6 145 155 Bohme Horst Pfeifer Hans Schneider Erich 1942 Dimeric thioketones Berichte der Deutschen Chemischen Gesellschaft 75B 7 900 909 doi 10 1002 cber 19420750722 Note This early report mistakes the trimer for the monomer Kroto H W Landsberg B M Suffolk R J Vodden A 1974 The photoelectron and microwave spectra of the unstable species thioacetaldehyde CH3CHS and thioacetone CH3 2CS Chemical Physics Letters 29 2 265 269 Bibcode 1974CPL 29 265K doi 10 1016 0009 2614 74 85029 3 ISSN 0009 2614 a b Derek Lowe June 11 2009 Things I Won t Work With Thioacetone In The Pipeline E Baumann amp E Fromm 1889 Ueber Thioderivate der Ketone Berichte der Deutschen Chemischen Gesellschaft 22 2 2592 2599 doi 10 1002 cber 188902202151 Chemical News and Journal of Industrial Science Chemical news office 1890 p 219 https www youtube com watch v LmAG8 V WQY https www youtube com watch v E wboFJZBTUExternal links EditThioacetone NIST Trithioacetone Aldrich Retrieved from https en wikipedia org w index php title Thioacetone amp oldid 1158234630, wikipedia, wiki, book, books, library,
