Sucrose octaacetate is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with formula or , an eight-fold

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

and

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...

. Its

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

can be described as that of sucrose with its eight

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

groups – replaced by

acetate An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...

groups –. It is a

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

line solid, colorless and odorless but intensely bitter. Sucrose octaacetate is used as an

inert ingredient An excipient is a substance formulated alongside the active ingredient of a medication, included for the purpose of long-term stabilization, bulking up solid formulations that contain potent active ingredients in small amounts (thus often referred ...

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...

s and

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

s, as a bitter additive.

History

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

Preparation

The compound can be prepared by the

exothermic reaction In thermochemistry, an exothermic reaction is a "reaction for which the overall standard enthalpy change Δ''H''⚬ is negative." Exothermic reactions usually release heat. The term is often confused with exergonic reaction, which IUPAC defines ...

of sucrose with

acetic anhydride Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH3CO)2O. Commonly abbreviated Ac2O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a col ...

at about 145 °C, with

sodium acetate Sodium acetate, CH3COONa, also abbreviated Na O Ac, is the sodium salt of acetic acid. This colorless deliquescent salt has a wide range of uses. Applications Biotechnological Sodium acetate is used as the carbon source for culturing bacteria ...

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

. The product can be purified by dissolution in ethanol and recrystallization.

Properties

Structure

The structure of the crystallized form was determined by J. D. Oliver and L. C. Strickland in 1984, using

X-ray diffraction X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

. The crystal system is

orthorombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a ...

, symmetry group P2₁2₁2₁, with parameters ''a'' = 1.835 nm, ''b''= 2.144 nm, ''c''= 0.835 nm, ''Z''=4, ''V''=3.285 nm³, ''D''_''x'' = 1.372 g/ mL. The

pyranose Pyranose is a collective term for saccharides that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom. There may be other carbons external to the ring. The name derives from its similarity ...

and

furanose A furanose is a collective term for carbohydrates that have a chemical structure that includes a five-membered ring system consisting of four carbon atoms and one oxygen atom. The name derives from its similarity to the oxygen heterocycle furan, bu ...

rings are in "chair" (⁴C₁) and "twist" (⁴T₁) conformations, respectively, unlike their conformations in saccharose.

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 Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) at ...

and

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

, from which it can be crystallized by evaporation. It is also soluble in

supercritical carbon dioxide Supercritical carbon dioxide (s) is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure. Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as ...

. It is a neutral molecule with no ionizable

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

atoms. The compound melts into a viscous liquid (29.54 poises at 100.2 °C), that becomes a clear

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...

y solid on cooling. The

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...

of the glassy form is 1.28 kg; L (at 20 °C), its

index of refraction In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

''n''_D²⁰ is 1.4660,its

dielectric constant The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insulat ...

is 4.5 (at 1

kHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that on ...

), and its

resistivity Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows ...

is 1.5 × 10¹⁴ Ω cm. It is

optically active Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circul ...

with �sub>D²⁴ = +59.79°. The compound slowly

hydrolyzes Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

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.

Organoleptic

The compound is odorless but intensely

bitter Bitter may refer to: Common uses * Resentment, negative emotion or attitude, similar to being jaded, cynical or otherwise negatively affected by experience * Bitter (taste), one of the five basic tastes Books * '' Bitter (novel)'', a 2022 nove ...

, being detectable at a concentration of 1–2 ppm. Adding 0.6 g of the compound to 1 kg of sugar renders it too bitter to eat.

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. 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.

Reactions

Sucrose octaacetate can be converted to other eightfold fatty acid esters of sucrose by reacting it with the appropriate

triglyceride A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as w ...

with

sodium methoxide Sodium methoxide is the simplest sodium alkoxide. With the formula , it is a white solid, which is formed by the deprotonation of methanol. Itis a widely used reagent in industry and the laboratory. It is also a dangerously caustic base. P ...

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).

Applications

Bitterant

Sucrose octaacetate has been used to determine tasters from non-tasters in mice, in clinical drug studies and

sweetener {{Wiktionary, sweetener A sweetener is a substance added to food or drink to impart the flavor of sweetness, either because it contains a type of sugar, or because it contains a sweet-tasting sugar substitute. Many artificial sweeteners have been ...

evaluations, and in taste physiology research. The product has also been used as a

bitterant A bitterant (or bittering agent) is a chemical that is added to a product to make it smell or taste bitter. Bitterants are commonly used as aversive agents to discourage the inhalation or ingestion of toxic substances. Examples of use *The add ...

and

aversive agent Aversive agents are unpleasantly flavored substances added to poisonous household goods to discourage children and animals from consuming them. Aversive agents are not intended to be harmful, only unpleasant. For example, to prevent children from co ...

. 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.

Flavoring agent

Sucrose octaacetate is used as a flavoring agent in foods and beverages, such as in

bitters Bitters (plural also ''bitters'') is traditionally an alcoholic preparation flavored with botanical matter for a bitter or bittersweet flavor. Originally, numerous longstanding brands of bitters were developed as patent medicines, but now are ...

and

ginger ale Ginger ale is a carbonated soft drink flavoured with ginger. It is consumed on its own or used as a mixer, often with spirit-based drinks. There are two main types of ginger ale. The golden style is credited to the Irish doctor Thomas Joseph ...

Plasticizer

Sucrose octaacetate has been used as an adhesive and as a

plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...

in lacquers and plastics. 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 Propionic acid (, from the Greek words πρῶτος : ''prōtos'', meaning "first", and πίων : ''píōn'', meaning "fat"; also known as propanoic acid) is a naturally occurring carboxylic acid with chemical formula CH3CH2CO2H. It is a liqu ...

or isobutyrate can be used.

Safety

Due to its low toxicity, sucrose octaacetate was authorized by the US Environment Protection Agency for use as an inert ingredient in pesticides, as

food additive Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salt ...

, and as a nail-biting and thumb-sucking deterrent in over-the-counter drug products.

References

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. A. Herzfeld (1887): ''Zeitschrift des Vereins der deutschen Zucker-Industrie'', volume 37, page 422. 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. J. D. Oliver and L. C. Strickland (1984): "tructure of sucrose octaacetate, C₂₈H₃₈O₁₉, at 173 K". ''Acta Crystallographica Section C'', volume 40, issue 5, pages 820-824. David R. Lide (1998): ''Handbook of Chemistry and Physics''. CRC Press. 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. 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,. George P. Touey and Herman E. Davis (1960):
Mixed esters of glucose and sucrose
. US Patent 2931802, assigned to Eastman Kodak Co. 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. US Environment Protection Agency, 21 CFR 172.515 US Environment Protection Agency, 21 CFR 175.105 US Environment Protection Agency, 21 CFR 310.536 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. 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 Disaccharides Bitter compounds Acetate esters