Trimethylsilanol

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Trimethylsilanol
Structural formula of trimethylsilanol TmsOH.svg
Structural formula of trimethylsilanol
Ball and stick model of trimethylsilanol Trimethylsilanol (structure).png
Ball and stick model of trimethylsilanol
Names
Preferred IUPAC name
Trimethylsilanol [1]
Other names
Hydroxy(trimethyl)silane [1]
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.012.650 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 213-914-1
MeSH Trimethylsilanol
PubChem CID
UNII
  • InChI=1S/C3H10OSi/c1-5(2,3)4/h4H,1-3H3
    Key: AAPLIUHOKVUFCC-UHFFFAOYSA-N
  • O[Si](C)(C)C
Properties
C3H10OSi
Molar mass 90.197 g·mol−1
AppearanceColourless liquid
Boiling point 99 °C (210 °F; 372 K)
Vapor pressure 21 mbar (20 °C) [2]
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Trimethylsilanol (TMS) is an organosilicon compound with the formula (CH3)3SiOH. The Si centre bears three methyl groups and one hydroxyl group. It is a colourless volatile liquid. [3] [4]

Contents

Occurrence

TMS is a contaminant in the atmospheres of spacecraft, where it arises from the degradation of silicone-based materials. [5] Specifically, it is the volatile product from the hydrolysis of polydimethylsiloxane, which are generally terminated with trimethylsilyl groups:

(CH3)3SiO[Si(CH3)2O]nR + H2O → (CH3)3SiOH + HO[Si(CH3)2O]nR

TMS and related volatile siloxanes are formed by hydrolysis of silicones-based containing materials, which are found in detergents and cosmetic products.

Traces of trimethylsilanol, together with other volatile siloxanes, are present in biogas and landfill gas, again resulting from the degradation of silicones. As their combustion forms particles of silicates and microcrystalline quartz, which cause abrasion of combustion engine parts, they pose problems for the use of such gases in combustion engines. [6]

Production

Trimethylsilanol is accessible by weakly basic hydrolysis of chlorotrimethylsilane, since the dimerization can thus be avoided. [7] Trimethylsilanol can also be obtained by the basic hydrolysis of hexamethyldisiloxane. [8]

Trimethylsilanol cannot be produced by simple hydrolysis of chlorotrimethylsilane as this reaction leads to the etherification product hexamethyldisiloxane, because of the by-product hydrochloric acid. [9]

Reactions

Trimethylsilanol is a weak acid with a pKa value of 11. [10] The acidity is comparable to that of orthosilicic acid, but much higher than the one of alcohols like tert-butanol (pKa 19 [10] ). Deprotonation with sodium hydroxide gives sodium trimethylsiloxide.

TMS reacts with the silanol groups (R3SiOH) giving silyl ethers.

Structure

In terms of its structure, the molecule is tetrahedral. The compound forms monoclinic crystals. [11]

Additional properties

The heat of evaporation is 45.64 kJ·mol−1, the evaporation entropy 123 J·K−1·mol−1. [2] The vapor pressure function according to Antoine is obtained as log10(P/1 bar) = A − B/(T + C) (P in bar, T in K) with A = 5.44591, B = 1767.766 K and C = −44.888 K in a temperature range from 291 K to 358 K. [2] Below the melting point at −4.5 °C, [12] The 1H NMR in CDCl3 shows a singlet at δ=0.14 ppm. [13]

Bioactivity

Like other silanols, trimethylsilanol exhibits antimicrobial properties. [14]


Related Research Articles

<span class="mw-page-title-main">Silicone</span> Type of polymer

A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking utensils, thermal insulation, and electrical insulation. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk.

<span class="mw-page-title-main">Trichlorosilane</span> Chemical compound

Trichlorosilane is an inorganic compound with the formula HCl3Si. It is a colourless, volatile liquid. Purified trichlorosilane is the principal precursor to ultrapure silicon in the semiconductor industry. In water, it rapidly decomposes to produce a siloxane polymer while giving off hydrochloric acid. Because of its reactivity and wide availability, it is frequently used in the synthesis of silicon-containing organic compounds.

<span class="mw-page-title-main">Silanol</span> Si–OH functional group in silicon chemistry

A silanol is a functional group in silicon chemistry with the connectivity Si–O–H. It is related to the hydroxy functional group (C–O–H) found in all alcohols. Silanols are often invoked as intermediates in organosilicon chemistry and silicate mineralogy. If a silanol contains one or more organic residue, it is an organosilanol.

<span class="mw-page-title-main">Polydimethylsiloxane</span> Chemical compound

Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, as its versatility and properties lead to many applications.

<span class="mw-page-title-main">Trimethylsilyl</span>

A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom [−Si(CH3)3], which is in turn bonded to the rest of a molecule. This structural group is characterized by chemical inertness and a large molecular volume, which makes it useful in a number of applications.

<span class="mw-page-title-main">Siloxane</span> Si–O–Si chemical bond

A siloxane is a functional group in organosilicon chemistry with the Si−O−Si linkage. The parent siloxanes include the oligomeric and polymeric hydrides with the formulae H(OSiH2)nOH and (OSiH2)n. Siloxanes also include branched compounds, the defining feature of which is that each pair of silicon centres is separated by one oxygen atom. The siloxane functional group forms the backbone of silicones, the premier example of which is polydimethylsiloxane. The functional group R3SiO− (where the three Rs may be different) is called siloxy. Siloxanes are manmade and have many commercial and industrial applications because of the compounds’ hydrophobicity, low thermal conductivity, and high flexibility.

Chlorosilanes are a group of reactive, chlorine-containing chemical compounds, related to silane and used in many chemical processes. Each such chemical has at least one silicon-chlorine bond. Trichlorosilane is produced on the largest scale. The parent chlorosilane is silicon tetrachloride.

Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R1R2R3Si−O−R4 where R4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis. Since R1R2R3 can be combinations of differing groups which can be varied in order to provide a number of silyl ethers, this group of chemical compounds provides a wide spectrum of selectivity for protecting group chemistry. Common silyl ethers are: trimethylsilyl (TMS), tert-butyldiphenylsilyl (TBDPS), tert-butyldimethylsilyl (TBS/TBDMS) and triisopropylsilyl (TIPS). They are particularly useful because they can be installed and removed very selectively under mild conditions.

<span class="mw-page-title-main">Trimethylsilyl chloride</span> Chemical compound

Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry.

<span class="mw-page-title-main">Organosilicon compound</span> Organometallic compound containing carbon–silicon bonds

Organosilicon compounds are organometallic compounds containing carbon–silicon bonds. Organosilicon chemistry is the corresponding science of their preparation and properties. Most organosilicon compounds are similar to the ordinary organic compounds, being colourless, flammable, hydrophobic, and stable to air. Silicon carbide is an inorganic compound.

<span class="mw-page-title-main">Decamethylcyclopentasiloxane</span> Chemical compound

Decamethylcyclopentasiloxane, also known as D5 and D5, is an organosilicon compound with the formula [(CH3)2SiO]5. It is a colorless and odorless liquid that is slightly volatile.

<span class="mw-page-title-main">Hexamethyldisiloxane</span> Chemical compound

Hexamethyldisiloxane (HMDSO) is an organosilicon compound with the formula O[Si(CH3)3]2. This volatile colourless liquid is used as a solvent and as a reagent in organic synthesis. It is prepared by the hydrolysis of trimethylsilyl chloride. The molecule is the protypical disiloxane and resembles a subunit of polydimethylsiloxane.

Hydrosilanes are tetravalent silicon compounds containing one or more Si-H bond. The parent hydrosilane is silane (SiH4). Commonly, hydrosilane refers to organosilicon derivatives. Examples include phenylsilane (PhSiH3) and triethoxysilane ((C2H5O)3SiH). Polymers and oligomers terminated with hydrosilanes are resins that are used to make useful materials like caulks.

Dimethyldichlorosilane is a tetrahedral, organosilicon compound with the formula Si(CH3)2Cl2. At room temperature it is a colorless liquid that readily reacts with water to form both linear and cyclic Si-O chains. Dimethyldichlorosilane is made on an industrial scale as the principal precursor to dimethylsilicone and polysilane compounds.

<span class="mw-page-title-main">Methyltrichlorosilane</span> Chemical compound

Methyltrichlorosilane, also known as trichloromethylsilane, is a monomer and organosilicon compound with the formula CH3SiCl3. It is a colorless liquid with a sharp odor similar to that of hydrochloric acid. As methyltrichlorosilane is a reactive compound, it is mainly used a precursor for forming various cross-linked siloxane polymers.

<span class="mw-page-title-main">Silsesquioxane</span> Molecular compound with applications in ceramics

A silsesquioxane is an organosilicon compound with the chemical formula [RSiO3/2]n. Silsesquioxanes are colorless solids that adopt cage-like or polymeric structures with Si-O-Si linkages and tetrahedral Si vertices. Silsesquioxanes are members of polyoctahedral silsesquioxanes ("POSS"), which have attracted attention as preceramic polymer precursors to ceramic materials and nanocomposites. Diverse substituents (R) can be attached to the Si centers. The molecules are unusual because they feature an inorganic silicate core and an organic exterior. The silica core confers rigidity and thermal stability.

<span class="mw-page-title-main">Trimethylsilyl iodide</span> Chemical compound

Trimethylsilyl iodide (iodotrimethylsilane or TMSI) is an organosilicon compound with the chemical formula (CH3)3SiI. It is a colorless, volatile liquid at room temperature.

<span class="mw-page-title-main">Octamethylcyclotetrasiloxane</span> Chemical compound

Octamethylcyclotetrasiloxane, also called D4, is an organosilicon compound with the formula [(CH3)2SiO]4. It is a colorless viscous liquid. It is a common cyclomethicone. It is widely used in cosmetics.

<span class="mw-page-title-main">Organosilanols</span> Organic compounds of the form R3–Si–OH

In organosilicon chemistry, organosilanols are a group of chemical compounds derived from silicon. More specifically, they are carbosilanes derived with a hydroxy group on the silicon atom. Organosilanols are the silicon analogs to alcohols. Silanols are more acidic and more basic than their alcohol counterparts and therefore show a rich structural chemistry characterized by hydrogen bonding networks which are particularly well studied for silanetriols.

<span class="mw-page-title-main">Hexamethylcyclotrisiloxane</span> Chemical compound

Hexamethylcyclotrisiloxane, also known as D3 and D3, is the organosilicon compound with the formula [(CH3)2SiO]3. It is a colorless or white volatile solid. It finds limited use in organic chemistry. The larger tetrameric and pentameric siloxanes, respectively octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, are of significant industrial interest, whereas 1,000–10,000 tonnes per year of the trimer is manufactured and/or imported in the European Economic Area.

References

  1. 1 2 Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 696. doi:10.1039/9781849733069-FP001. ISBN   978-0-85404-182-4.
  2. 1 2 3 Grubb, W.T.; Osthoff, R.C.: Physical Properties of Organosilicon Compounds. II. Trimethylsilanol and Triethylsilanol in J. Am. Chem. Soc. 75 (1953) 2230–2232; doi:10.1021/ja01105a061.
  3. ↑ Paul D. Lickiss: The Synthesis and Structure of Organosilanols, Advances in Inorganic Chemistry 1995, Volume 42, Pages 147–262, doi : 10.1016/S0898-8838(08)60053-7.
  4. ↑ Vadapalli Chandrasekhar, Ramamoorthy Boomishankar, Selvarajan Nagendran: Recent Developments in the Synthesis and Structure of Organosilanols, Chem. Rev. 2004, volume 104, pp 5847–5910, doi : 10.1021/cr0306135.
  5. ↑ Trimethylsilanol, Harold L. Kaplan, Martin E. Coleman, John T. James: Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 1 (1994).
  6. ↑ http://epics.ecn.purdue.edu/bgi/Documents/Fall%25202009/Removal_of_Siloxanes_.pdf [ dead link ]
  7. ↑ J.A. Cella, J.C. Carpenter: Procedures for the preparation of silanols in J. Organomet. Chem. 480 (1994), 23–23; doi : 10.1016/0022-328X(94)87098-5
  8. ↑ M. Lovric, I. Cepanec, M. Litvic, A. Bartolincic, V. Vinkovic: Croatia Chem. Acta 80 (2007), 109–115
  9. ↑ Didier Astruc: Organometallic Chemistry and Catalysis. Springer Science & Business Media, 2007, ISBN   978-3-540-46129-6, S. 331 ( , p. 331, at Google Books).
  10. 1 2 T. Kagiya, Y. Sumida, T. Tachi: An Infrared Spectroscopic Study of hydrogen Bonding Interaction. Structural Studies of Proton-donating and -accepting Powers in Bull. Chem. Soc. Jpn. 43 (1970), 3716–3722.
  11. ↑ R. Minkwitz, S. Schneider: Die Tieftemperaturkristallstruktur von Trimethylsilanol. In: Zeitschrift für Naturforschung B. 53, 1998, S. 426–429 (PDF, freier Volltext).
  12. ↑ Batuew et al. in Doklady Akademii Nauk SSSR 95 (1954) 531.
  13. ↑ Hamada, Tomoaki; Manabe, Kai; Kobayashi, Shū (13 January 2006). "Catalytic Asymmetric Mannich-Type Reactions Activated by ZnF2 Chiral Diamine in Aqueous Media". Chemistry - A European Journal. 12 (4): 1205–1215. doi:10.1002/chem.200500673. PMID   16267871 . Retrieved 16 March 2021.
  14. ↑ Yun-mi Kim, Samuel Farrah, Ronald H. Baney (2006). "Silanol – A novel class of antimicrobial agent". Electronic Journal of Biotechnology. 9 (2): 176–180. doi:10.2225/vol9-issue2-fulltext-4.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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