Sucrose octaacetate

{{chembox | Watchedfields = changed | verifiedrevid = 441320670 | ImageFile =Sucrose octaacetate.png | ImageSize = | IUPACName = 1,3,4,5-Tetra-O-acetyl-β-D-fructofuranosyl α-D-glucopyranoside 2,3,4,6-tetraacetate | SystematicName = (2R,3R,4S,5R,6R)-6-{[(2S,3S,4R,5R)-2,3,4,5-Tetrakis(acetyloxy)oxolan-2-yl]oxy}oxane-2,3,4,5-tetrayl tetraacetate | OtherNames = Acetic acid [(2S,3S,4R,5R)-4-acetoxy-2,5-bis(acetoxymethyl)-2-{[(2R,3R,4S,5R,6R)-3,4,5-triacetoxy-6- (acetoxymethyl)-2-tetrahydropyranyl]oxy}-3-tetrahydrofuranyl] ester |Section1=!Identifiers

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3D model (JSmol)

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| ECHA InfoCard | 100.004.339 |-




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  • CC(=O)OC[C@@H]1[C@H]([C@@H]([C@H]([C@H](O1)O[C@]2([C@H]([C@@H]([C@H](O2)COC(=O)C)OC(=O)C)OC(=O)C)COC(=O)C)OC(=O)C)OC(=O)C)OC(=O)C

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| C28H38O19

|- | Molar mass

| 678.59 g/mol

|- | Appearance | colorless needles |- | Odor | odourless |- | Density | 1.27 g/cm3 at 16 °C |- | Melting point | 86.5 °C (187.7 °F; 359.6 K)

|- | Boiling point | 250 °C (482 °F; 523 K) at 1 mmHg

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| slightly soluble in water |-

| Solubility | soluble in ethanol, diethyl ether, acetone, benzene, chloroform,[1] toluene[2] |- |Section3= }}

Sucrose octaacetate is a chemical compound with formula C
28H
38O
19or (C
2H
3O
2)
8(C
12H
14O
3), an eight-fold ester of sucrose and acetic acid. Its molecule can be described as that of sucrose C
12H
22O
11 with its eight hydroxyl groups HO– replaced by acetate groups H
3C–CO
2–. It is a crystalline solid, colorless and odorless but intensely bitter.[2]

Sucrose octaacetate is used as an inert ingredient in pesticides and herbicides, as a bitter additive.

History

The preparation of sucrose octaacetate was first described in 1865 by P. Schutzenberger,[3] but its purification and characterization were first published by A. Herzfeld in 1887.[4][2]

Preparation

The compound can be prepared by the exothermic reaction of sucrose with acetic anhydride at about 145 °C, with sodium acetate as catalyst.[2] The product can be purified by dissolution in ethanol and recrystallization.[5]

Properties

Structure

The structure of the crystallized form was determined by J. D. Oliver and L. C. Strickland in 1984, using X-ray diffraction. The crystal system is orthorhombic, symmetry group P212121, with parameters a = 1.835 nm, b= 2.144 nm, c= 0.835 nm, Z=4, V=3.285 nm3, Dx = 1.372 g/mL. The pyranose and furanose rings are in "chair" (4C1) and "twist" (4T1) conformations, respectively, unlike their conformations in saccharose.[6]

Physico-chemical

Sucrose octaacetate is only slightly soluble in water (sources give 0.25 to 1.4 g/L at room temperature) but is soluble in many common organic solvents such as toluene and ethanol, from which it can be crystallized by evaporation.[2] It is also soluble in supercritical carbon dioxide.[7] It is a neutral molecule with no ionizable hydrogen atoms.[5]

The compound melts into a viscous liquid (29.54 poises at 100.2 °C), that becomes a clear glassy solid on cooling.[2]

The density of the glassy form is 1.28 kg;L (at 20 °C), its index of refraction nD20 is 1.4660,its dielectric constant is 4.5 (at 1 kHz), and its resistivity is 1.5 × 1014 Ω cm. It is optically active with [α]D24 = +59.79°.[2]

The compound slowly hydrolyzes in water: 0.25% of the acetate ester bonds were broken by boiling in water for 1 hour, and 0.20% after standing in water at 40 °C for 5 days.

Sucrose octaacetate decomposes at about 285 °C, but can be distilled at reduced pressure at 260 °C.[2]

Organoleptic

The compound is odorless but intensely bitter, being detectable at a concentration of 1–2 ppm.[2] Adding 0.6 g of the compound to 1 kg of sugar renders it too bitter to eat.[5]

Melting point and possible polymorphism

There has been significant discrepancy in the reported melting point of the crystalline compound. Five reports spanning 1880 to 1928 gave it as 69–70 °C. In 1930, a crystal form was reported to melt at 75 °C. In 1936, another report described a different crystal form and a melting point of 83 °C. In 1940, the same authors found 89 °C. All reports since then have given melting points in 83–89 °C range.[5]

It was conjectured that the differences could be due to polymorphism; namely, that the compound could crystallize in two or more different crystal structures, with different melting points. However, modern studies, including X-ray diffraction, failed to find any evidence of polymorphism.[5]

Reactions

Sucrose octaacetate can be converted to other eightfold fatty acid esters of sucrose by reacting it with the appropriate triglyceride with sodium methoxide as catalyst. This way one can obtain sucrose octacaprylate (C8 chain), octacaprate (C10, m.p −24 °C) octalaurate (C12, 10 °C), octamyristate (C14, 34 °C), octapalmitate, (C16, 50.5 °C), octastearate (C18, 61 °C), octaoleate (C18 cis-9), octaelaidate (C18 trans-9, 7.4 °C), and octalinoleate (C18 cis-9,12).[8]

Applications

Bitterant

Sucrose octaacetate has been used to determine tasters from non-tasters in mice,[9] in clinical drug studies and sweetener evaluations,[5] and in taste physiology research.[5]

The product has also been used as a bitterant and aversive agent.[10] Until 1993, the compound was the active ingredient of over-the-counter preparations to discourage thumb sucking and nail biting. It has also been used in sprays and lotions to prevent dog licking, and as an additive to deter ingestion of pesticides and other toxic products. [5]

Flavoring agent

Sucrose octaacetate is used as a flavoring agent in foods and beverages, such as in bitters and ginger ale.[5]

Plasticizer

Sucrose octaacetate has been used as an adhesive and as a plasticizer in lacquers and plastics.[5] While the crystalline character of the pure compound is an obstacle for this latter application, mixed esters where some acetate groups are replaced by propionate or isobutyrate can be used.[11]

Safety

Due to its low toxicity, sucrose octaacetate was authorized by the US Environment Protection Agency for use as an inert ingredient in pesticides,[12] as food additive,[13][14] and as a nail-biting and thumb-sucking deterrent in over-the-counter drug products.[10]

See also

References
  1. David R. Lide (1998): Handbook of Chemistry and Physics. CRC Press. ISBN 0-8493-0594-2
  2. Gerald J. Cox, John H. Ferguson, and Mary L. Dodds (1933): "III. Technology of Sucrose Octaäcetate and Homologous Esters". Industrial & Engineering Chemistry, volume 25, issue 9, pages 968–970. doi:10.1021/ie50285a006
  3. P. Schutzenberger (1865): "Action de l'acide acétique anhydre sur la cellulose, les sucres, la mannite et ses congénères". Comptes rendus des séances de l'académie des sciences, volume 61, page 485.
  4. A. Herzfeld (1887): Zeitschrift des Vereins der deutschen Zucker-Industrie, volume 37, page 422.
  5. William Craig Stagner, Shalini Gaddam, Rudrangi Parmar, and Ajay Kumar Ghanta (2019): "Sucrose octaacetate". Chapter 5 of Profiles of Drug Substances, Excipients and Related Methodology, volume 44, pages 267-291 doi:10.1016/bs.podrm.2019.02.002
  6. J. D. Oliver and L. C. Strickland (1984): "Structure of sucrose octaacetate, C28H38O19, at 173 K". Acta Crystallographica Section C, volume 40, issue 5, pages 820-824. doi:10.1107/S0108270184005850
  7. Anu Antony, Jyothi P. Ramachandran, Resmi M. Ramakrishnan, and Poovathinthodiyil Raveendran (2018): "Sizing of paper with sucrose octaacetate using liquid and supercritical carbon dioxide as a green alternative medium". Journal of CO2 Utilization, volume 28, pages 306-312. doi:10.1016/j.jcou.2018.10.011
  8. Ronald J. Jandacek and Marjorie R. Webb (1978): "Physical properties of pure sucrose octaesters". Chemistry and Physics of Lipids, volume 22, issue 2, pages 163-176. doi:10.1016/0009-3084(78)90042-7
  9. David B. Harder, Christopher G. Capeless, John C. Maggio, John D. Boughter, Jr, Kimberley S. Gannon, Glayde Whitney, and Edwin A. Azen (1992): "Intermediate sucrose octa-acetate sensitivity suggests a third allele at mouse bitter taste locus Soa and Soa-Rua identity". Chemical Senses, volume 17, issue 4, pages 391–401,. doi:10.1093/chemse/17.4.391
  10. US Environment Protection Agency, 21 CFR 310.536
  11. George P. Touey and Herman E. Davis (1960): "Mixed esters of glucose and sucrose". US Patent 2931802, assigned to Eastman Kodak Co.
  12. Christina M. Jarvis (2005): "Reassessment of the Exemption from the Requirement of a Tolerance for Sucrose Octaacetate (CAS Reg. No. 126-14-7)". Mamorandum dated 2005-12-21, CFR 180.910.
  13. US Environment Protection Agency, 21 CFR 172.515
  14. US Environment Protection Agency, 21 CFR 175.105
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