121-43-7 Usage
Description
Trimethyl borate, a member of the borate esters class, is a water-white, moisture-sensitive liquid that appears denser than water with vapors heavier than air. It is obtained by the formal condensation of three equivalents of methanol with boric acid. Trimethyl borate is characterized by its miscibility with ether, methanol, hexane, and tetrahydrofuran, and it forms an azeotrope with methanol at 55°C. It is stable in an anhydrous state but decomposes into methanol and boric acid in the presence of water. Additionally, it is used as a solvent and fungicide for fruit.
Uses
1. Organic Synthesis:
Trimethyl borate is used as a reagent in organic synthesis, playing a crucial role in the production of resins, waxes, and paints. It acts as a methylation agent, facilitating various chemical reactions.
2. Flame Retardants, Anti-oxidants, and Corrosion Inhibitors:
As a boron source, trimethyl borate is utilized in the preparation of flame retardants, anti-oxidants, and corrosion inhibitors, enhancing the safety and durability of materials.
3. Boronic Acid Preparation:
Trimethyl borate reacts with Grignard reagents or organolithium compounds to yield dimethyl boronates, which, upon subsequent aqueous acid treatment, afford corresponding boronic acids. These boronic acids or esters serve as useful intermediates in various cross-coupling reactions.
4. Suzuki Coupling and Chan-Lam Coupling:
The resultant boronic acids or esters from trimethyl borate are employed in cross-coupling reactions such as Suzuki coupling and Chan-Lam coupling, which are essential in the synthesis of complex organic molecules.
5. Borate Esters and Suzuki Coupling Reaction:
Trimethyl borate is used as a precursor of borate esters, which find application in the Suzuki coupling reaction, a widely used method for the formation of carbon-carbon bonds in organic chemistry.
6. Neutron Detector Gas:
Trimethyl borate is utilized as a neutron detector gas in the presence of a scintillation counter, playing a vital role in nuclear science and technology.
7. Diboranane Reactions:
Trimethyl borate acts as a promoter in diborane reactions, enhancing the efficiency and effectiveness of these chemical processes.
8. Solvent and Fungicide for Fruit:
In addition to its applications in the chemical industry, trimethyl borate is also used as a solvent and fungicide for fruit, providing protection against fungal infections and extending the shelf life of fruits.
Used in Chemical Industry:
Trimethyl borate is used as a reagent for organic synthesis, a boron source for flame retardants, anti-oxidants, and corrosion inhibitors, and a precursor of borate esters for Suzuki coupling reactions.
Used in Nuclear Science and Technology:
Trimethyl borate is used as a neutron detector gas in the presence of a scintillation counter, contributing to the advancement of nuclear research and safety.
Used in Agricultural Industry:
Trimethyl borate is used as a solvent and fungicide for fruit, providing protection against fungal infections and extending the shelf life of fruits.
Preparation
The preparation method of trimethyl borate1. The direct reaction between boric acid and methanol is as follows:3CH30H+H3B03→B (OCH3) 3+3H20Usually the trimethyl borate formed in the reaction forms an azeotrope with excess methanol and is distilled out together, and then the trimethyl borate is obtained by separating the azeotrope.2. The direct reaction between boron oxide and methanol is as follows:B203+6CH30H→2B (OCH3) 3+3H203. Borax, methanol and sulfuric acid are directly reacted, and the reaction formula is :Na2B4O7.1OH2O+12CH30H+2H2S04→4B (OCH3)3+2NaHS04+17H20
Reactions
Trimethyl borate B(OCH3)3 is a popular borate ester used in organic synthesis.borate esters are prepared from alkylation of trimethyl borate:ArMgBr + B(OCH3 )3 → MgBrOCH3 + ArB(OCH3 )2ArB(OCH3 )2 + 2H2O → ArB(OH)2 + 2 HOCH3
Air & Water Reactions
Highly flammable. Rapidly decomposes in water.
Reactivity Profile
Borates, such as Trimethyl borate, behave similarly to esters in that they react with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters/borates with alkali metals and hydrides.
Health Hazard
May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
Fire Hazard
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
Safety Profile
Moderately toxic by
ingestion, skin contact, and intraperitoneal
routes. An eye irritant. A very dangerous fire
hazard when exposed to heat, flame, or
oxidizers. Moderately explosive when
exposed to flame. Will react with water or
steam to produce toxic and flammable
vapors. To fight fire, use dry chemical, CO2,
spray, foam. When heated to decomposition
it emits acrid smoke and irritating fumes.
See also ESTERS and BORON
COMPOUNDS.
Purification Methods
Carefully fractionate the borate through a gauze-packed column. Re-distil and collect it in weighed glass vials and seal them. Keep it away from moisture. It undergoes alkyl exchange with alcohols and forms azeotropes, e.g. with MeOH the azeotrope consists of 70% (MeO)3B and 30% MeOH with b 52-54o/760mm, d 0.87. [Charnley et al. J Chem Soc 2288 1952, Gerrard & Lappert Chem Ind (London) 53 1952, Schlesinger et al. J Am Chem Soc 75 213 1953.] It has also been dried with Na and then distilled. [Beilstein 1 IV 1269.]
Check Digit Verification of cas no
The CAS Registry Mumber 121-43-7 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,2 and 1 respectively; the second part has 2 digits, 4 and 3 respectively.
Calculate Digit Verification of CAS Registry Number 121-43:
(5*1)+(4*2)+(3*1)+(2*4)+(1*3)=27
27 % 10 = 7
So 121-43-7 is a valid CAS Registry Number.
InChI:InChI:1S/C3H9BO3/c1-5-4(6-2)7-3/h1-3H3
121-43-7Relevant articles and documents
de Moor,J.E.,van der Kelen,G.P.
, p. 235 - 241 (1966)
Burg, A. B.,Schlesinger, H. I.
, p. 4020 - 4025 (1933)
Infrared spectra of B(OMe)3, ClB(OMe)2 and Cl2BOMe species, isolated CH streching frequencies and bond strengths
McKean, D. C.,Coats, A. M.
, p. 409 - 420 (1989)
Infrared spectra in the gas phase are reported over the range 3100-500 cm-1 for species of B(OMe)3, ClB(OMe)2 and Cl2BOMe, with CH3, CD3 and CHD2 substitution.A detailed analysis of νCH and νCD data in all three species of Cl2BOMe yields strong evidence for the presence of three kinds of CH bond, two of them weak and one of them strong.The methyl group is then twisted, probably through 10-20 deg, out of the eclipsed or staggered conformation.The CHD2 spectra of the di and trimethoxy compounds are less susceptible to analysis, but suggest also the presence of two weak and strong bonds, the former increasing in weakness as the number of methoxy groups increases.This is as expected from the increased competition likely between the lone pair electrons for the empty boron orbital.The spectra of the CD3 species permit a clear assignment of νBO, δsCH3, δsCD3 and δasCD3 modes.In Cl(COCH3)2, νsBO lies at 1278 cm-1.
Action of Lewis acids upon base-pentaborane(9) adducts
Burg, Anton B.,Maya, Leon
, p. 942 - 944 (1975)
-
-
, p. 213 - 215 (1953)
-
Burg,Mahler
, p. 4242 (1957)
The alcoholysis of carbon monoxide borane
Malone, Leo J.
, p. 1039 - 1040 (1968)
-
Study of the reaction between boron trifluoride methanol complex and sodium methoxide
Wuke, Lang,Weijiang, Zhang,Jiao, Xu,Lei, Zhang
, p. 1530 - 1540 (2014)
The reaction between boron trifluoride methanol complex and sodium methoxide in methanol solution was investigated using conductivity as the reaction indicator. The reaction conditions were examined and a mechanism of this reaction was proposed. Moreover, proper reaction conditions were proposed for boric acid preparation using this reaction. 2014
The degradation of biscarborane
Hawthorne,Owen,Wiggins
, p. 1304 - 1306 (1971)
-
-
Brown,Mead
, p. 3614 (1956)
-
Wiesboeck, R. A.,Hawthorne, M. F.
, p. 1642 - 1643 (1964)
Reaction of a 14-vertex carborane with nucleophiles: Formation of nido-C2B12, nido-C2B11, and closo-CB11 carborane anions
Zhang, Jian,Zheng, Fangrui,Chan, Hoi-Shan,Xie, Zuowei
, p. 9786 - 9791 (2009)
Nucleophilic reactions of a 14-vertex closo-carborane are reported. 2, 3-(CH2)3-2,3-C2B12H12 (1) reacts with MeOH at 70 °C to give closo-CB11 anions [1,2-(CH2)3CH(OMe)-1-CB11, H10] - ([2a]-), [1,2-(CH2)3CH(OMe)-1- CB11, H10]- ([2b]- ), and [1,2-(CH2)2CH=CH-1-CB11H10] - ([2c]- ). It is suggested that [2c]- is an intermediate for the isomerizatlon from [2a]- to [2b]- . Treatment of 1 with MeOH/Me3N, 'BuOK or LINMe2 affords nido-C2B12 species [8,9-(CH2) 3-μ-11, 12-(Nu)BH-8,9-C2B11H 11]-(Nu = MeO ([3a]-), BuO ([3b]-), and Me2N ([3c]-)). In the presence of acid such as HCl, anions [3]- are converted to 1. However, [3] undergo deboration reaction, in the presence of bases, to generate a nidO-C2B 11 anion [8, 9-(CH2)38,9-C2B 11H12]- ([4]-) that can also be formed directly from the reaction of 1 with excess CsF or piperidine. Mechanistic studies show that [3a]- is the first intermediate in the reaction of 1 with MeOH and [4]- Is unlikely an intermediate.
Garrett, P. M.,Tebbe, F. N.,Hawthorne, M. F.
, p. 5016 - 5017 (1964)
Acetate-catalyzed hydroboration of CO2 for the selective formation of methanol-equivalent products
Dagorne, Samuel,Dos Santos, Jo?o H. Z.,Jacques, Béatrice,López, Carlos Silva,Nieto Faza, Olalla,Schrekker, Henri S.,Sokolovicz, Yuri C. A.,Specklin, David
, p. 2407 - 2414 (2020/05/13)
The present study details the use of the acetate anion, an inexpensive and robust anion, as a CO2 hydroboration catalyst for the selective formation, in most cases, of methanol-equivalent borane products. Thus, upon heating (90 °C, PhBr), tetrabutylammonium, sodium and potassium acetate (1, 2 and 3, respectively) effectively catalyze CO2 hydroboration by pinacolborane (pinB-H) to afford CO2 reduction products HOCOBpin (A), pinBOCH2OBpin (B) and methoxyborane (C). In most cases, high selectivity for product C with higher borane loading and longer reaction time with a TON of up to 970 was observed. The reduction catalysis remains efficient at low catalyst loading (down to 0.1 mol%) and may also be performed under solvent-free conditions using salt 1 as a catalyst, reflecting the excellent robustness and stability of the acetate anion. In control experiments, a 1/1 1/pinB-H mixture was found to react fast with CO2 at room temperature to produce formate species [pinB(O2CH)(OAc)][N(nBu)4] (5) through CO2 insertion into the B-H bond. DFT calculations were also performed to gain insight into the acetate-mediated CO2 hydroboration catalysis, which further supported the crucial role of acetate as a Lewis base in CO2 functionalization catalysis by pinB-H. The DFT-estimated mechanism is in line with experimental data and rationalizes the formation of the most thermodynamically stable reduction product C through acetate catalysis.
A Versatile NHC-Parent Silyliumylidene Cation for Catalytic Chemo- And Regioselective Hydroboration
Leong, Bi-Xiang,Lee, Jiawen,Li, Yan,Yang, Ming-Chung,Siu, Chi-Kit,Su, Ming-Der,So, Cheuk-Wai
supporting information, p. 17629 - 17636 (2019/11/11)
This study describes the first use of a silicon(II) complex, NHC-parent silyliumylidene cation complex [(IMe)2SiH]I (1, IMe =:C{N(Me)C(Me)}2) as a versatile catalyst in organic synthesis. Complex 1 (loading: 10 mol %) was shown to act as an efficient catalyst (reaction time: 0.08 h, yield: 94%, TOF = 113.2 h-1 reaction time: 0.17 h, yield: 98%, TOF = 58.7 h-1) for the selective reduction of CO2 with pinacolborane (HBpin) to form the primarily reduced formoxyborane [pinBOC(-O)H]. The activity is better than the currently available base-metal catalysts used for this reaction. It also catalyzed the chemo- and regioselective hydroboration of carbonyl compounds and pyridine derivatives to form borate esters and N-boryl-1,4-dihydropyridine derivatives with quantitative conversions, respectively. Mechanistic studies show that the silicon(II) center in complex 1 activated the substrates and then mediated the catalytic hydroboration. In addition, complex 1 was slightly converted into the NHC-borylsilyliumylidene complex [(IMe)2SiBpin]I (3) in the catalysis, which was also able to mediate the catalytic hydroboration.
