141-78-6 Usage
Chemical Description
Different sources of media describe the Chemical Description of 141-78-6 differently. You can refer to the following data:
1. Ethyl acetate is a colorless liquid used as a solvent.
2. Ethyl acetate is a common organic solvent.
3. Ethyl acetate is a colorless, volatile liquid that is used as a solvent.
4. Ethyl acetate is a colorless liquid used as a solvent in various applications.
5. Ethyl acetate is a colorless liquid with a fruity odor and the chemical formula CH3COOCH2CH3.
6. Ethyl acetate is an ester commonly used as a solvent.
7. Ethyl acetate is a solvent used for extraction and dilution.
8. Ethyl acetate, hexanes, acetone, methyl tert-butyl ether, dichloromethane, and methanol are solvents used in column chromatography.
9. Ethyl acetate is an organic solvent that was used to partition some of the chemicals during purification.
10. Ethyl acetate is a colorless liquid that is commonly used as a solvent in various chemical reactions.
11. Ethyl acetate and petroleum ether are solvents used in the elution process.
12. Ethyl acetate and light petroleum are solvents used in flash chromatography.
13. Ethyl acetate is a solvent used to extract the product from the reaction mixture.
14. Ethyl acetate is a common solvent used in organic chemistry.
15. Ethyl acetate is a colorless liquid with a fruity odor and the chemical formula C4H8O2.
16. Ethyl acetate is a colorless liquid used as a solvent in various chemical reactions.
17. Ethyl acetate is a common solvent used in various applications.
18. Ethyl acetate is a polar solvent used in chromatography and extractions.
19. Ethyl acetate is a colorless liquid used as a solvent and extraction agent.
20. Ethyl acetate is a solvent used for extraction.
organic ester compound
Ethyl Acetate is an organic ester compound with a molecular formula of C4H8O2 (commonly abbreviated as EtOAc or EA), appears as a colorless liquid. It is highly miscible with all common organic solvents (alcohols, ketones, glycols, esters), which make it a common solvent for cleaning, paint removal and coatings.
Ethyl acetate is found in alcoholic beverages, cereal crops, radishes, fruit juices, beer, wine, spirits etc. It has a fruity characteristic odor that is commonly recognized in glues, nail polish remover, decaffeinating tea and coffee, and cigarettes. Due to its agreeable aroma and low cost, this chemical is commonly used and manufactured in large scale in the world, as over 1 million tons annually.
ethyl acetate structure
Chemical Properties
Different sources of media describe the Chemical Properties of 141-78-6 differently. You can refer to the following data:
1. Ethyl acetate (structure shown above) is the most familiar ester to many chemistry students and possibly the ester with the widest range of uses. Esters are structurally derived from carboxylic acids by replacing the acidic hydrogen by an alkyl or aryl group. Ethyl acetate itself is a colourless liquid at room temperature with a pleasant "fruity" smell, b.p. 77°C.
Ethyl acetate has many uses, such as artificial fruit essences and aroma enhancers, artificial flavours for confectionery, ice cream and cakes, as a solvent in many applications (including decaffeinating tea and coffee) for varnishes and paints (nail varnish remover), and for the manufacture of printing inks and perfumes.
2. Ethyl acetate has a pleasant ethereal fruity, brandy-like odor, reminiscent of pineapple, somewhat nauseating in high
concentration. It has fruity sweet taste when freshly diluted in water. Ethyl acetate is probably one of the most used of all flavor
chemicals by volume. Ethyl acetate is slowly decomposed by moisture and then acquires an acid status due to the acetic acid formed.
Purification and water removal methods
Ethyl acetate generally has a content of 95% to 98% containing a small amount of water, ethanol and acetic acid. It can be further purified as following: add 100mL of acetic anhydride into 1000mL of ethyl acetate; add 10 drops of concentrated sulfuric acid, heat and reflux for 4h to remove impurities such as ethanol and water, and then further subject to distillation. Distillate is oscillated by 20~30g of anhydrous potassium carbonate and further subject to re-distillation. The product has a boiling point of 77 °C and purity being over 99%.
Uses
Different sources of media describe the Uses of 141-78-6 differently. You can refer to the following data:
1. ▼▲
Industry
Applications
Role/Benefit
Flavor and essence
Food flavor
Used largely to prepare bananas, pears, peaches, pineapple and grape scent food flavors, etc
Alcoholic essence
Used slightly as fragrance volatile
Perfume essence
Used slightly as fragrance volatile
Chemical manufacture
Production of acetamide, acetyl acetate, methyl heptanone, etc
Organic chemical raw materials
Production of organic acid
Extracting agent
Laboratory
Dilution and extraction
Supply excellent dissolving capacity
Chromatographic analysis
Standard material
Column chromatography and extractions
Main component of mobile phase
Reaction solvent
Be prone to hydrolysis and transesterification
Chemical analysis
Thermometer calibration for sugar separation
?Standard material
Determination of bismuth, boron, gold, molybdenum, platinum and thallium
Solvent
Entomology
Insect collecting and study
Used as effective asphyxiant to kill the collected insect quickly without destroying it
Textile industry
Cleaning agent
Supply excellent dissolving capacity
Printing
Flexographic and rotogravure printing
Dissolve the resin, control the viscosity and modify the drying rate
Electronics industry
Viscosity reducer
Reduce the viscosity of resins used in photoresist formulations
Paint manufacture
Solvent
Dissolve and dilute the paints
Health & personal care products
The formulation of nail polish, nail polish removers and other manicuring products
Supply excellent dissolving capacity
Pharmaceutical
Medicine manufacturing
Extraction agent; intermediate
Cosmetics
Aroma enhancer
In perfume to enhance aroma
Others
Tanning extracts
Used for desulfurization of tanning, cigarette materials, oil field drilling, metal flotation, descaling, etc
Production of adhesive
Solvent
Extract many compounds (phosphorus, cobalt, tungsten, arsenic) from aqueous solution
Extracting agent
2. Ethyl acetate is used as a solvent for varnishes, lacquers, and nitrocellulose; as anartificial fruit flavor; in cleaning textiles;and in the manufacture of artificial silk andleather, perfumes, and photographic filmsand plates (Merck 1996). Ethyl Acetate is generally used as a solvent in organic reactions. Environmental contaminants; Food contaminants.
3. Ethyl acetate is used primarily as a solvent and diluent, being favored because of its low cost, low toxicity, and agreeable odor. For example, it is commonly used to clean circuit boards and in some nail varnish removers (acetone and acetonitrile are also used). Coffee beans and tea leaves are decaffeinated with this solvent.It is also used in paints as an activator or hardener.[citation needed] Ethyl acetate is present in confectionery, perfumes, and fruits. In perfumes, it evaporates quickly, leaving only the scent of the perfume on the skin.3 – 1 - Laboratory uses In the laboratory, mixtures containing ethyl acetate are commonly used in column chromatography and extractions. Ethyl acetate is rarely selected as a reaction solvent because it is prone to hydrolysis and trans esterification. 3 – 2 - Occurrence in wines Ethyl acetate is the most common ester in wine, being the product of the most common volatile organic acid — acetic acid, and the ethyl alcohol generated during the fermentation. The aroma of ethyl acetate is most vivid in younger wines and contributes towards the general perception of "fruitiness" in the wine. 3 – 3 - Entomological killing agent In the field of entomology, ethyl acetate is an effective asphyxiant for use in insect collecting and study. In a killing jar charged with ethyl acetate, the vapors will kill the collected (usually adult) insect quickly without destroying it. Because it is not hygroscopic, ethyl acetate also keeps the insect soft enough to allow proper mounting suitable for a collection.
4. Pharmaceutic aid (flavor); artificial fruit essences; solvent for nitrocellulose, varnishes, lacquers, and aeroplane dopes; manufacture of smokeless powder, artificial leather, photographic films and plates, artificial silk, perfumes; cleaning textiles, etc.
Production
Industrial production of ethyl acetate is mainly classified into three processes.
The first one is a classical Fischer esterification process of ethanol with acetic acid in presence of acid catalyst. This process needs acid catalyst2 such as sulphuric acid, hydrochloride acid, ptoluene sulfonic acid etc. This mixture converts to the ester in about 65% yield at room temperature.?
CH3CH2OH + CH3COOH ? CH3COOC2H5 + H2O
The reaction can be accelerated by acid catalysis and the equilibrium can be shifted to the right by removal of water.
The second one is Tishchenko Reaction of acetaldehyde using aluminium triethoxide as a catalyst. In Germany and Japan, most ethyl acetate is produced via the Tishchenko process.?
2 CH3CHO → CH3COOC2H5
This method has been proposed by two different routes; (i) dehydrogenative process, which uses copper or palladium based catalyst and (ii) the oxidative one, which employs, PdO supported catalysts.
The third one, which has been recently commercialized, is addition of acetic acid to ethylene using clay and heteroploy acid7 as a catalyst.?
CH2= CH2 + CH3COOH → CH3COOC2H5?
The processes, however, have some disadvantages; both the conventional esterification and addition of acetic acid to ethylene need stock tanks and apparatus for several feed stocks. Moreover, they use acetic acid that causes apparatus corrosion. Although Teshchenko Reaction uses only one feed and it is a non-corrosive material, it is difficult to handle acetaldehyde because is not available outside of petrochemical industrial area.
In such circumstances, an improved process of ethyl acetate production is strongly desired.
Extinguishing agent
dry powder, dry sand, carbon dioxide, foam, and 1211 fire extinguishing agent
Professional standards
TWA 1400 mg/m3; STEL 2000 mg/m3
Description
Ethyl acetate (systematically, ethyl ethanoate, commonly abbreviated EtOAc or EA) is the organic compound with the formula CH3COOCH2CH3. This colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers, decaffeinating tea and coffee, and cigarettes (see list of additives in cigarettes). Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent. The combined annual production in 1985 of Japan, North America, and Europe was about 400,000 tons. In 2004, an estimated 1.3M tons were produced worldwide.
Physical properties
Clear, colorless, mobile liquid with a pleasant, sweet fruity odor. Experimentally determined
detection and recognition odor threshold concentrations were 23 mg/m3 (6.4 ppmv) and 48 mg/m3
(13.3 ppmv), respectively (Hellman and Small, 1974). Cometto-Mu?iz and Cain (1991) reported
an average nasal pungency threshold concentration of 67,300 ppmv.
Occurrence
Although it has been reported present in some natural fruital aromas and in some distillates (rum, rum ether),
it has not been reported yet as a constituent of essential oils; it has been identified also in the petals of Magnolia fuscata. Reported
found in many foods including fresh and cooked apple, apricot, banana (169 ppm), sweet and sour cherry, citrus peel oils and juices,
blueberry, cranberry, black currants, raspberry, blackberry, guava, passion fruit, melon, peaches, papaya, pineapple, cabbage, onion,
leek, potato, tomato (3 to 6 ppm), clove, ginger, vinegar, breads, cheeses (0.2 to 0.8 ppm), butter (2 ppm), yogurt, milk, meats, cognac,
beer (4 to 64 ppm), whiskies, cider, sherry, grape wines, rum, cocoa, coffee, tea, filberts, peanuts, popcorn, oats, honey, soybeans,
coconut, olive oil (0.02 ppm) and olive.
Production Methods
Different sources of media describe the Production Methods of 141-78-6 differently. You can refer to the following data:
1. Ethyl acetate can be manufactured by the slow distillation of a
mixture of ethanol and acetic acid in the presence of concentrated
sulfuric acid. It has also been prepared from ethylene using an
aluminum alkoxide catalyst.
2. Ethyl acetate is synthesized in industry mainly via the classic Fischer esterification reaction of ethanol and acetic acid. This mixture converts to the ester in about 65% yield at room temperature: CH3CH2OH + CH3COOH ? CH3COOCH2CH3 + H2O The reaction can be accelerated by acid catalysis and the equilibrium can be shifted to the right by removal of water. It is also prepared in industry using the Tishchenko reaction, by combining two equivalents of acetaldehyde in the presence of an alkoxide catalyst: 2 CH3CHO → CH3COOCH2CH3.
Preparation
Ethyl acetate is made by esterification of acetic acid with ethanol, from acetaldehyde, or by the direct addition of ethylene to acetic acid. BP started a 220,000 tonne/year plant in 2001 to operate the last of these processes, known as AVADA. Ethylene and acetic acid react in the presence of a heteropolyacid catalyst to give ethyl acetate at a claimed high selectivity and 99.97% purity. This is the world’s largest ethyl acetate plant and is motivated by its increasing use as a more “acceptable” solvent than hydrocarbons.
In some countries, where ethanol is expensive or there is surplus acetaldehyde capacity, ethyl acetate is made by a Tishchenko reaction. Sasol in South Africa was said to be investigating such a process in the early 2000s. Ethanol is a solvent for surface coatings, cleaning preparations, and cosmetics. Industrial ethanol is aerobically fermented to white vinegar (dilute acetic acid) of the type used for pickling. Gourmet vinegars—wine vinegar, cider vinegar, and so on, made by fermentation of alcoholic beverages—are also available. Ten percent of industrial ethanol production was used for vinegar in the United States in 2001.
Reactions
Ethyl acetate can be hydrolyzed in acidic or basic conditions to regain acetic acid and ethanol. The use of an acid catalyst accelerates the hydrolysis, which is subject to the Fischer equilibrium mentioned above. In the laboratory, and usually for illustrative purposes only, ethyl esters are typically hydrolyzed in a two step process starting with a stoichiometric amount of strong base, such as sodium hydroxide. This reaction gives ethanol and sodium acetate, which is unreactive toward ethanol: CH3CO2C2H5 + Na OH → C2H5OH + CH3CO2Na The rate constant is 0.111 dm3 / mol.sec at 25 °C.
Aroma threshold values
Detection: 5 ppb to 5 ppm
General Description
Ethyl acetate, a carboxylate ester, is bio-friendly organic solvent with wide range of industrial applications. Its synthesis by reactive distillation and by acceptorless dehydrogenative dimerization of ethanol has been explored. Its utility as a less toxic alternative to diethyl ether in the formalin-ether (F-E) sedimentation procedure for intestinal parasites has been investigated. Its ability as an acyl acceptor in the immobilized lipase-mediated preparation of biodiesel from crude vegetable oils has been examined. The complete degradation of ethyl acetate to CO2 using manganese octahedral molecular sieve (OMS-2) has been investigated.
Air & Water Reactions
Highly flammable. Slightly soluble in water. Ethyl acetate is slowly hydrolyzed by moisture.
Reactivity Profile
Ethyl acetate is also sensitive to heat. On prolonged storage, materials containing similar functional groups have formed explosive peroxides. Ethyl acetate may ignite or explode with lithium aluminum hydride. Ethyl acetate may also ignite with potassium tert-butoxide. Ethyl acetate is incompatible with nitrates, strong alkalis and strong acids. Ethyl acetate will attack some forms of plastics, rubber and coatings. Ethyl acetate is incompatible with oxidizers such as hydrogen peroxide, nitric acid, perchloric acid and chromium trioxide. Violent reactions occur with chlorosulfonic acid. . SOCl2 reacts with esters, such as Ethyl acetate, forming toxic SO2 gas and water soluble/toxic acyl chlorides, catalyzed by Fe or Zn (Spagnuolo, C.J. et al. 1992. Chemical and Engineering News 70(22):2.).
Health Hazard
The acute toxicity of ethyl acetate is low. Ethyl acetate vapor causes eye, skin, and
respiratory tract irritation at concentrations above 400 ppm. Exposure to high
concentrations may lead to headache, nausea, blurred vision, central nervous system
depression, dizziness, drowsiness, and fatigue. Ingestion of ethyl acetate may cause
gastrointestinal irritation and, with larger amounts, central nervous system
depression. Eye contact with the liquid can produce temporary irritation and
lacrimation. Skin contact produces irritation. Ethyl acetate is regarded as a substance
with good warning properties.
No chronic systemic effects have been reported in humans, and ethyl acetate has not
been shown to be a human carcinogen, reproductive, or developmental toxin
Flammability and Explosibility
Ethyl acetate is a flammable liquid (NFPA rating = 3), and its vapor can travel a considerable distance to an ignition source and "flash back." Ethyl acetate vapor forms explosive mixtures with air at concentrations of 2 to 11.5% (by volume). Hazardous gases produced in ethyl acetate fires include carbon monoxide and carbon dioxide. Carbon dioxide or dry chemical extinguishers should be used for ethyl acetate fires.
Chemical Reactivity
Reactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Pharmaceutical Applications
In pharmaceutical preparations, ethyl acetate is primarily used as a
solvent, although it has also been used as a flavoring agent. As a
solvent, it is included in topical solutions and gels, and in edible
printing inks used for tablets.Ethyl acetate has also been shown to increase the solubility of
chlortalidone and to modify the polymorphic crystal forms
obtained for piroxicam pivalate, mefenamic acid, and fluconazole,and has been used in the formulation of microspheres. Ethyl acetate has been used as a solvent in the preparation of a
liposomal amphotericin B dry powder inhaler formulation.(9) Its use
as a chemical enhancer for the transdermal iontophoresis of insulin
has been investigated.
In food applications, ethyl acetate is mainly used as a flavoring
agent. It is also used in artificial fruit essence and as an extraction
solvent in food processing.
Safety Profile
Potentially poisonous by ingestion. Toxicity depends upon alcohols in question, generally ethanol with methanol as a denaturant. A flammable liquid and dangerous fire hazard; can react vigorously with oxidzing materials. Moderate explosion hazard. See ETHANOL, METHYL ALCOHOL, and n-PROPYL ALCOHOL.
Safety
Ethyl acetate is used in foods, and oral and topical pharmaceutical
formulations. It is generally regarded as a relatively nontoxic and
nonirritant material when used as an excipient.
However, ethyl acetate may be irritant to mucous membranes,
and high concentrations may cause central nervous system
depression. Potential symptoms of overexposure include irritation
of the eyes, nose, and throat, narcosis, and dermatitis.
Ethyl acetate has not been shown to be a human carcinogen or a
reproductive or developmental toxin.
The WHO has set an estimated acceptable daily intake of ethyl
acetate at up to 25 mg/kg body-weight.
In the UK, it has been recommended that ethyl acetate be
temporarily permitted for use as a solvent in food and that the
maximum concentration consumed in food should be set at
1000 ppm.
LD50 (cat, SC): 3.00 g/kg
LD50 (guinea-pig, oral): 5.50 g/kg
LD50 (guinea-pig, SC): 3.00 g/kg
LD50 (mouse, IP): 0.709 g/kg
LD50 (mouse, oral): 4.10 g/kg
LD50 (rabbit, oral): 4.935 g/kg
LD50 (rat, oral): 5.62 g/kg
Synthesis
By reacting acetic acid and ethanol in the presence of sulfuric acid; by distillation of sodium potassium, or lead acetate
with ethanol in the presence of sulfuric acid; by polymerizatin of acetaldehyde in the presence of aluminum ethylate or aluminum
acetate as catalysts.
Potential Exposure
This material is used as a solvent for
nitrocellulose and lacquer. It is also used in making dyes,flavoring and perfumery, and in smokeless powder
manufacture
Carcinogenicity
Ethyl acetate was not mutagenic in bacterial
assays; it was not genotoxic in a number
of in vivo assays but did cause chromosomal
damage in hamster cells in vitro.
Ethyl acetate has a fruity odor detectable
at 10ppm.
The 2003 ACGIH threshold limit valuetime-
weighted average (TLV-TWA) for ethyl
acetate is 400pm (1440mg/m3).
Environmental fate
Biological. Heukelekian and Rand (1955) reported a 5-d BOD value of 1.00 g/g which is 54.9%
of the ThOD value of 1.82 g/g.
Photolytic. Reported rate constants for the reaction of ethyl acetate and OH radicals in the
atmosphere (296 K) and aqueous solution are 1.51 x 10-12 and 6.60 x 10-13 cm3/molecule?sec,
respectively (Wallington et al., 1988b).
Chemical/Physical. Hydrolyzes in water forming ethanol and acetic acid (Kollig, 1993). The
estimated hydrolysis half-life at 25 °C and pH 7 is 2.0 yr (Mabey and Mill, 1978).
Metabolism
Ethyl acetate is hydrolysed to ethyl alcohol, which is then partly excreted in the expired air and urine. The rest is metabolized, the acetate fraction becoming incor porated in the body pool (Fassett, 1963).
storage
Ethyl acetate should be stored in an airtight container, protected
from light and at a temperature not exceeding 30°C. Ethyl acetate is
slowly decomposed by moisture and becomes acidic; the material
can absorb up to 3.3% w/w water.Ethyl acetate decomposes on heating to produce ethanol and
acetic acid, and will emit acrid smoke and irritating fumes. It is
flammable and its vapor may travel a considerable distance to an
ignition source and cause a ‘flashback’.
The alkaline hydrolysis of ethyl acetate has been shown to be
inhibited by polyethylene glycol and by mixed micelle systems.
Shipping
UN1173 Ethyl acetate, Hazard Class: 3; Labels:
3-Flammable liquid.
Purification Methods
The most common impurities in EtOAc are water, EtOH and acetic acid. These can be removed by washing with aqueous 5% Na2CO3, then with saturated aqueous CaCl2 or NaCl, and drying with K2CO3, CaSO4 or MgSO4. More efficient drying is achieved if the solvent is further dried with P2O5, CaH2 or molecular sieves before distillation. CaO has also been used. Alternatively, ethanol can be converted to ethyl acetate by refluxing with acetic anhydride (ca 1mL per 10mL of ester), the liquid is then fractionally distilled, dried with K2CO3 and redistilled. [Beilstein 2 III 127.]
Toxicity evaluation
Ethyl acetate is rapidly hydrolyzed to ethanol and acetic acid.
When ethyl acetate was injected intraperitoneal at 1.6 g kg-1,
hydrolysis to acetic acid and ethanol occurred rapidly. The
biological half-life value of the conversion of ethyl acetate to
ethanol was found to be between 5 and 10 min. At doses higher
than 1.6 g kg-1 in rats the rate of hydrolysis exceeded the
ethanol oxidation leading to the ethanol accumulation in the
vascular system.
Incompatibilities
Ethyl acetate can react vigorously with strong oxidizers, strong
alkalis, strong acids, and nitrates to cause fires or explosions. It also
reacts vigorously with chlorosulfonic acid, lithium aluminum
hydride, 2-chloromethylfuran, and potassium tert-butoxide.
Waste Disposal
Dissolve or mix the material
with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal,
state, and local environmental regulations must be
observed. Consult with environmental regulatory agencies for guidance on acceptable disposal practices.
Generators of waste containing this contaminant (≧100 kg/
mo) must conform with EPA regulations governing storage,
transportation, treatment, and waste disposal.
Regulatory Status
Included in the FDA Inactive Ingredients Database (oral tablets and
sustained-action tablets; topical and transdermal preparations).
Included in nonparenteral medicines licensed in the UK (tablets,
topical solutions, and gels). Ethyl acetate is also accepted for use in
food applications in a number of countries including the UK.
Included in the Canadian List of Acceptable Non-medicinal
Ingredients.
Check Digit Verification of cas no
The CAS Registry Mumber 141-78-6 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,4 and 1 respectively; the second part has 2 digits, 7 and 8 respectively.
Calculate Digit Verification of CAS Registry Number 141-78:
(5*1)+(4*4)+(3*1)+(2*7)+(1*8)=46
46 % 10 = 6
So 141-78-6 is a valid CAS Registry Number.
InChI:InChI=1/C4H8O2/c1-3-6-4(2)5/h3H2,1-2H3
141-78-6Relevant articles and documents
-
Lane et al.
, p. 6492 (1968)
-
ESI-MS Insights into Acceptorless Dehydrogenative Coupling of Alcohols
Vicent, Cristian,Gusev, Dmitry G.
, p. 3301 - 3309 (2016)
Acceptorless dehydrogenative coupling (ADC) reactions catalyzed by a series of Ru and Os complexes were studied by ESI-MS. Important ethoxo, 1-ethoxyethanolate, and hydride intermediates were intercepted in the ADC of ethanol to ethyl acetate. Collision-induced dissociation (CID) experiments were applied as a structure elucidation tool and as a probe of the propensity of the reaction intermediates to evolve acetaldehyde, ethyl acetate, and H2, relevant to the catalytic cycle. The key mechanistic step producing ethyl acetate from the 1-ethoxyethanolate intermediates was documented. Energy-dependent CID experiments demonstrated the importance of a vacant coordination site for efficient production of ethyl acetate. The versatility and potential broad applicability of ESI-MS and its tandem version with CID was further illustrated for the ADC reaction of alcohols with amines, affording amides. A mechanism related to that found for the ester synthesis is plausible, with the key step involving formation of a hemiaminaloxide intermediate.
Total oxidation of ethanol over Au/Ce0.5Zr0.5O2 cordierite monolithic catalysts
Topka, Pavel,Klementová, Mariana
, p. 130 - 137 (2016)
The aim of this work was to propose the methods for gold introduction during the preparation of monolithic catalysts and to investigate their effect on catalyst properties. Two types of catalysts were prepared: (i) monoliths washcoated with gold/ceria-zirconia powder, and (ii) gold deposited on the monoliths washcoated with ceria-zirconia powder. An important part of the work was the characterization of the catalysts, in particular Au particle size and redox properties. Catalytic performance and selectivity were evaluated using ethanol gas-phase oxidation. It was shown that the enhanced reducibility of the catalysts with higher Au dispersion leads to improved catalytic performance.
A dinuclear strontium(II) complex as substrate-selective catalyst of ester cleavage
Cacciapaglia,Di Stefano,Mandolini
, p. 5926 - 5928 (2001)
-
Iodide-induced differential control of metal ion reduction rates: synthesis of terraced palladium-copper nanoparticles with dilute bimetallic surfaces
King, Melissa E.,Personick, Michelle L.
, p. 22179 - 22188 (2018)
Metal nanoparticles possessing a high density of atomic steps and edge sites provide an increased population of undercoordinated surface atoms, which can enhance the catalytic activity of these materials compared to low-index faceted or bulk materials. Simply increasing reactivity, however, can lead to a concurrent increase in undesirable, non-selective side products. The incorporation of a second metal at these reactive stepped features provides an ideal avenue for finely attenuating reactivity to increase selectivity. A major challenge in synthesizing bimetallic nanomaterials with tunable surface features that are desirable for fundamental catalytic studies is a need to bridge differences in precursor reduction potentials and metal lattice parameters in structures containing both a noble metal and a non-noble metal. We report the use of low micromolar concentrations of iodide ions as a means of differentially controlling the relative reduction rates of a noble metal (palladium) and a non-noble metal (copper). The iodide in this system increases the rate of reduction of palladium ions while concurrently slowing the rate of copper ion reduction, thus providing a degree of control that is not achievable using most other reported means of tuning metal ion reduction rate. This differential control of metal ion reduction afforded by iodide ions enables access to nanoparticle growth conditions in which control of palladium nanoparticle growth by copper underpotential deposition becomes possible, leading to the generation of unique terraced bimetallic particles. Because of their bimetallic surface composition, these terraced nanoparticles exhibit increased selectivity to acetaldehyde in gas phase ethanol oxidation.
Radical-Induced Reductive Deamination of Amino Acid Esters
Barton, Derek H. R.,Bringmann, Gerhard,Motherwell, Wiliam B.
, p. 68 - 70 (1980)
-
Acetic acid hydrogenation to ethanol over supported Pt-Sn catalyst: Effect of Bronsted acidity on product selectivity
Rakshit, Pranab Kumar,Voolapalli, Ravi Kumar,Upadhyayula, Sreedevi
, p. 78 - 90 (2018)
Gas phase hydrogenation of acetic acid was investigated over a series of SiO2-Al2O3 supported platinum-tin (Pt-Sn) catalysts. The active metals were impregnated over the support using incipient wetness technique and the resulting catalyst samples were characterized by Transmission electron microscopy, Hydrogen pulse chemisorption, BET surface area analyzer, Powder X-Ray diffraction, NH3-Temperature programmed desorption and H2-Temperature programmed reduction methods. Acetic acid hydrogenation reaction was carried out in an isothermal fixed bed catalyst testing unit. The results revealed that bimetallic Pt-Sn catalyst forms Pt-Sn alloy upon reduction which favors acetic acid hydrogenation to ethanol compared to competing side product CH4. The magnitude of Pt-Sn alloy formed per unit mass of catalyst depends upon the Pt/ Sn molar ratio in the calcined catalyst sample. 3 wt% Pt- 3 wt% Sn on SiO2-Al2O3 was found to be the optimum catalyst loading, resulting in 81% acetic acid conversion with 95% ethanol selectivity at 2 MPa and 270 °C. Further increase in ethanol selectivity would require prevention of esterification of acetic acid with ethanol, which leads to formation of ethyl acetate as by-product. The effect of catalyst acidity on acetic acid conversion and ethanol selectivity was studied and it was observed that proton donating capability of the support leads to the formation of ethyl acetate as by-product which, in turn, reduces ethanol selectivity. The ethanol synthesis reaction and esterification reaction over Bronsted acid sites takes place in series. The rate of esterification reaction was found to be highly dependent on the Bronsted acid density of the catalysts. Other catalyst parameters have little role on ethyl acetate yield.
A green approach to ethyl acetate: Quantitative conversion of ethanol through direct dehydrogenation in a Pd-Ag membrane reactor
Zeng, Gaofeng,Chen, Tao,He, Lipeng,Pinnau, Ingo,Lai, Zhiping,Huang, Kuo-Wei
, p. 15940 - 15943 (2012)
Pincers do the trick: The conversion of ethanol to ethyl acetate and hydrogen was achieved using a pincer-Ru catalyst in a Pd-Ag membrane reactor. Near quantitative conversions and yields could be achieved without the need for acid or base promoters or hydrogen acceptors (see scheme).
-
Connor,Adkins
, p. 3420,3421, 3422 (1932)
-
Catalytic Conversion of Ethanol to n-Butanol Using Ruthenium P-N Ligand Complexes
Wingad, Richard L.,Gates, Paul J.,Street, Steven T. G.,Wass, Duncan F.
, p. 5822 - 5826 (2015)
We report several ruthenium catalysts incorporating mixed donor phosphine-amine ligands for the upgrade of ethanol to the advanced biofuel n-butanol, which show high selectivity (≥90%) at good (up to 31%) conversion. In situ formation of catalysts from mixtures of [RuCl2(η6-p-cymene)]2 and 2-(diphenylphosphino)ethylamine (1) shows enhanced activity at initial water concentrations higher than those of our previously reported diphosphine systems. Preliminary mechanistic studies (electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy) suggest the possibility of ligand-assisted proton transfer in some derivatives.
Catalytic Transformation of Ethanol over Microporous Vanadium Silicate Molecular Sieves with MEL Structure (VS-2)
Kannan,Sen,Sivasanker
, p. 304 - 310 (1997)
The transformation of ethanol was carried out over vanadium silicate molecular sieves with MEL topology (VS-2) with different Si/V atomic ratios in the temperature range 523-623 K. The reaction was performed in a fixed-bed down-flow reactor at atmospheric pressure. Acetaldehyde, diethyl ether, and ethylene were the major products along with small amounts of acetone, acetic acid, ethyl acetate, and carbon oxides. The conversion increased while the selectivity toward acetaldehyde decreased with increase in reaction temperature. The kinetics of the reaction (at 5% conversion) indicated a nearly first-order dependence of the rate of formation of the major products on ethanol. The formation of acetaldehyde is suggested to be mainly through the involvement of the vanadyl species (V=O) while diethyl ether production is controlled by the simultaneous involvement of V=O and V-O-Si associated with vanadium in the lattice. The intrinsic activity of vanadium incorporated into the zeolite framework is nearly 10 times that of the vanadium present in the impregnated sample. The nature of the sites involved in the formation of the different products, as elucidated from spectroscopic techniques (NMR and ESR), and the possible reaction mechanisms are proposed.
Production of Pure Aqueous13C-Hyperpolarized Acetate by Heterogeneous Parahydrogen-Induced Polarization
Kovtunov, Kirill V.,Barskiy, Danila A.,Shchepin, Roman V.,Salnikov, Oleg G.,Prosvirin, Igor P.,Bukhtiyarov, Andrey V.,Kovtunova, Larisa M.,Bukhtiyarov, Valerii I.,Koptyug, Igor V.,Chekmenev, Eduard Y.
, p. 16446 - 16449 (2016)
A supported metal catalyst was designed, characterized, and tested for aqueous phase heterogeneous hydrogenation of vinyl acetate with parahydrogen to produce13C-hyperpolarized ethyl acetate for potential biomedical applications. The Rh/TiO2catalyst with a metal loading of 23.2 wt % produced strongly hyperpolarized13C-enriched ethyl acetate-1-13C detected at 9.4 T. An approximately 14-fold13C signal enhancement was detected using circa 50 % parahydrogen gas without taking into account relaxation losses before and after polarization transfer by magnetic field cycling from nascent parahydrogen-derived protons to13C nuclei. This first observation of13C PHIP-hyperpolarized products over a supported metal catalyst in an aqueous medium opens up new possibilities for production of catalyst-free aqueous solutions of nontoxic hyperpolarized contrast agents for a wide range of biomolecules amenable to the parahydrogen induced polarization by side arm hydrogenation (PHIP-SAH) approach.
High-purity alkoxychlorosilanes as new precursors for precipitation of silica
Mirskov,Rakhlin,Adamovich,Voronkov
, p. 194 - 196 (2008)
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Synthesis of acetic acid from ethanol-water mixture over Cu/ZnO-ZrO 2-Al2O3 catalyst
Brei, Volodymyr V.,Sharanda, Mykhailo E.,Prudius, Svitlana V.,Bondarenko, Eugenia A.
, p. 196 - 200 (2013)
It was shown that acetic acid can be obtained from aqueous ethanol (6-40 mol%) solutions over Cu/ZnO-ZrO2-Al2O3 catalyst at 250-320 C and atmospheric pressure. Selectivity of 80-90% and space-time yield of acetic acid up to 9 mmol gcat-1 h-1 at 60-80% ethanol conversion were obtained while processing 14-37 mol% aqueous ethanol solutions. Hydrogen was generated in an amount ~2 moles per 1 mole of acetic acid as a co-product.
Revised Mechanisms for Aldehyde Disproportionation and the Related Reactions of the Shvo Catalyst
Gusev, Dmitry G.,Spasyuk, Denis M.
, p. 6851 - 6861 (2018)
It is widely believed that the Shvo catalyst (1) dissociates to form two active species in solution: the 18-electron hydride RuH(CO)2[η5-C5(OH)Ph4] (2) and the naked 16-electron complex Ru(CO)2[η4-C5(=O)Ph4] (3). This combined experimental/computational study demonstrates that a sustained presence of 3 is not viable in the reactions of alcohols and organic carbonyls; thus, 3 is better treated as nonexistent under the typical catalytic conditions. We propose a modified view where the key catalytic species are the hydride 2 and the 18-electron metal alkoxide intermediate Ru(OR)(CO)2[η5-C5(OH)Ph4] existing in equilibrium with the corresponding alcohol complex. An X-ray crystallographic study of 2 revealed an interesting dihydrogen-bonded dimer structure in the solid state. The mechanistic ideas of this paper explain the highly efficient Tishchenko-like aldehyde disproportionation reaction with the Shvo catalyst. Additionally, our observations explain why 1 is inefficient for hydrogenation of ethyl acetate and for the acceptorless dehydrogenative coupling of ethanol. Our findings provide practical guidance for future catalyst design on the basis of the Shvo ruthenium dimer prototype.
Deeper Mechanistic Insight into Ru Pincer-Mediated Acceptorless Dehydrogenative Coupling of Alcohols: Exchanges, Intermediates, and Deactivation Species
Nguyen, Duc Hanh,Trivelli, Xavier,Capet, Frédéric,Swesi, Youssef,Favre-Réguillon, Alain,Vanoye, Laurent,Dumeignil, Franck,Gauvin, Régis M.
, p. 4719 - 4734 (2018)
The mechanism of acceptorless dehydrogenative coupling reaction (ADC) of alcohols to esters catalyzed by aliphatic pincer PHNP ruthenium complexes was experimentally studied. Relevant intermediate species involved in the catalytic cycle were isolated and structurally characterized by single-crystal X-ray diffraction studies, and their reactivity (including toward substrates related to the catalytic process) was probed. VT NMR studies unveiled several chemical exchanges connecting the Ru amido hydride, the Ru alkoxide, and the alcohol substrate. Under catalytic conditions, in situ IR spectroscopy monitoring demonstrated the production of ester via aldehyde as intermediate. A Tishchenko-like pathway is proposed as the main path for the production of ester from aldehyde, involving alkoxide and hemiacetaloxide Ru species (the latter being identified in the reaction mixture by NMR). Catalytic system deactivation under base-free conditions was found to be related to water traces in the reaction medium (either as impurity or derived from aldol reactions) that lead to the formation of catalytically inactive acetato Ru complexes. These react with alkali metal alkoxides to afford catalytically active Ru species. In line with this observation, running the ADC reaction in the presence of water scavengers or alkoxides allows maintaining sustained catalytic activity.
Impact of the Oxygen Vacancies on Copper Electronic State and Activity of Cu-Based Catalysts in the Hydrogenation of Methyl Acetate to Ethanol
Xi, Yushan,Wang, Yue,Yao, Dawei,Li, Antai,Zhang, Jingyu,Zhao, Yujun,Lv, Jing,Ma, Xinbin
, (2019)
Reducible oxides supported copper-based catalysts have been widely used in ester hydrogenations due to their excellent catalytic performance. However, the role of surface oxygen vacancies is still unclear. Here, we fabricated four copper-based catalysts u
RADICAL TELOMERIZATION OF 3,3,3-TRIFLUOROPROPENE WITH 2-METHYL-1,3-DIOXOLANE
Terent'ev, A.B.,Pastushenko, E.V.,Kruglov, D.E.,Ryabinina, T.A.
, p. 2197 - 2200 (1992)
The telomerization of 3,3,3-trifluoropropene with 2-methyl-1,3-dioxolane gives predominantly cyclic telomers as shown by 13C NMR and gas chromatography-mass spectrometry.This reaction is accompanied by the rearrangement of transient free radical intermediates via 1,5-H-migration. Keywords: radicals, addition, dioxolane, telomers, telomerization, kinetics.
Effect of Support in Ethanol Oxidation on Molybdenum Oxide
Zhang, Weimin,Desikan Anantha,Oyama, S. Ted
, p. 14468 - 14476 (1995)
The oxidation of ethanol on MoO3 supported on SiO2, Al2O3, and TiO2 was studied in a flow reactor at atmospheric pressure.The reactivity sequence followed the order MoO3/TiO2 > MoO3/Al2O3 > MoO3/SiO2 and correlated with the reducibility of the surface molybdenum species.Ethanol oxidation produces mainly acetaldehyde, diethyl ehter, and ethylene through ethoxide type intermediates adsorbed on different sites (M=O, Mo-O-Mo, or Mo-O-M).Two types of ethoxide species were identified using laser Raman spectroscopy under in situ conditions and could be associated with the Mo=O and Mo-O-Mo sites.Although rates were strongly affected by the support, suggesting that activity was controlled by a term in the preexponential factor.The link to reducibility and the existence of a common ethoxide intermediate indicated that the controlling factor was likely to be the electronic partition function associated with the density of electron-accepting levels in the molybdate-support complex.
Facile synthesis of homogeneous CsxWO3 nanorods with excellent low-emissivity and NIR shielding property by a water controlled-release process
Guo, Chongshen,Yin, Shu,Yan, Mei,Sato, Tsugio
, p. 5099 - 5105 (2011)
A systematic investigation of the synthesis of homogenous Cs xWO3 nanorods by a designed water-controlled release process was carried out. The results revealed that the uniform rod-like Cs xWO3 nanoparticles with a Cs/W atomic ratio of ca. 0.33 can be obtained by using 20 vol% CH3COOH-80 vol% CH 3CH2OH mixed solution as a reaction solvent at 240°C for 20 h. The morphology of products were changed depending on the speed of water-releasing process, meanwhile, the Cs/W atomic ratio could be controlled by both the amount of released water and the reaction temperature. Cs xWO3 nanorods showed a high transmittance in the visible light region and excellent shielding ability of near infrared (NIR) lights, indicating that CsxWO3 nanorods have a suitable characteristic as solar filter applications. The Royal Society of Chemistry 2011.
Highly selective 1-butanol obtained from ethanol catalyzed by mixed metal oxides: Reaction optimization and catalyst structure behavior
Rechi Siqueira, Marcos,Micali Perrone,Metzker, Gustavo,de Oliveira Lisboa, Daniela Correa,Thoméo, Jo?o Cláudio,Boscolo, Maurício
, (2019)
Synthesis and characterization of a copper mixed metal oxide obtained from hydrotalcite precursor as well as catalytic runs for ethanol conversion to 1-butanol are described. Applying the surface response model, the reaction was optimized reaching an ethanol conversion of 79.6% into gaseous phase (69% of yield) and condensed phase (31% of yield) products using a batch reactor at 350 °C for 5 h. The main product of the condensed phase was 1-butanol with 25.4% yield and 32% selectivity, these results being among the higher ones reported for this reaction in the literature. Recycling catalyst experiments demonstrated that, for at least four cycles, the ethanol conversion remains almost constant but the 1-butanol yield and selectivity both decreased. XRD, EPR, surface area measurements and acidity/basicity experiments carried out after the first and fourth catalyst recycling cycles show major modifications in the initial mixed metal oxide structure and copper oxidation state indicating that the active catalytic species increases during the first catalytic run.
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Ruggli et al.
, p. 411,413 (1939)
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Thermal decomposition of acetyl propionyl peroxide in acetone-d6
Skakovskii,Stankevich,Tychinskaya,Shirokii,Choban,Murashko,Rykov
, p. 1719 - 1725 (2004)
The kinetics of thermolysis of acetyl propinyl peroxide in acetone-d 6 in the temperature range 323-373 K was studied using NMR spectroscopy and the effect of chemically induced nuclear polarization. The peroxide decomposes in acetone at rates comparable with the rates of thermolysis in alcohols, yielding numerous products. In the examined temperature range, the solvent molecules act as efficient donors of deuterium atoms, forming acetylmethyl-d5 radicals which recombine to a significant extent with the peroxide radicals. A scheme of the processes involved in decomposition of the peroxide was suggested. The parameters of the Arrhenius equation for the peroxide decomposition were determined. 2004 MAIK "Nauka/ Interperiodica".
The Reaction of with Triethoxysilane in the Presence of PPh3: a New Method for Synthesis of
Marciniec, Bogdan,Maciejewski, Hieronim,Gulinski, Jacek
, p. 717 - 718 (1995)
The reaction of with triethoxysilane in the presence of PPh3 is examined under oxygen-free conditions, permitting isolation of 1 formed by elimination of one acac ligand (as protonated and hydrosilylated product) from the nickel complex with its simultaneous silylation which is followed by C-O bond cleavage in triethoxysilyl ligand via a mechanism involving transfer of an ethyl group to Ni with elimination of pentaethoxyhydrodisiloxane in the excess of triethoxysilane.
DEUTERIUM ISOTOPE EFFECTS IN THE THERMAL DECOMPOSITION OF β-HYDROXY KETONES AND β-HYDROXY ESTERS
Quijano, J.,Rodriguez, M. M.,Yepes, M. del S.,Gallego, L.H.
, p. 3555 - 3558 (1987)
Small primary and cumulative secondary isotope effects are determined experimentally by thermolysis of various β-hydroxy ketones and β-hydroxy esters.
Dehydrogenative ester synthesis from enol ethers and water with a ruthenium complex catalyzing two reactions in synergy
Ben-David, Yehoshoa,Diskin-Posner, Yael,Kar, Sayan,Luo, Jie,Milstein, David,Rauch, Michael
supporting information, p. 1481 - 1487 (2022/03/07)
We report the dehydrogenative synthesis of esters from enol ethers using water as the formal oxidant, catalyzed by a newly developed ruthenium acridine-based PNP(Ph)-type complex. Mechanistic experiments and density functional theory (DFT) studies suggest that an inner-sphere stepwise coupled reaction pathway is operational instead of a more intuitive outer-sphere tandem hydration-dehydrogenation pathway.
Dual utility of a single diphosphine-ruthenium complex: A precursor for new complexes and, a pre-catalyst for transfer-hydrogenation and Oppenauer oxidation
Mukherjee, Aparajita,Bhattacharya, Samaresh
, p. 15617 - 15631 (2021/05/19)
The diphosphine-ruthenium complex, [Ru(dppbz)(CO)2Cl2] (dppbz = 1,2-bis(diphenylphosphino)benzene), where the two carbonyls are mutually cis and the two chlorides are trans, has been found to serve as an efficient precursor for the synthesis of new complexes. In [Ru(dppbz)(CO)2Cl2] one of the two carbonyls undergoes facile displacement by neutral monodentate ligands (L) to afford complexes of the type [Ru(dppbz)(CO)(L)Cl2] (L = acetonitrile, 4-picoline and dimethyl sulfoxide). Both the carbonyls in [Ru(dppbz)(CO)2Cl2] are displaced on reaction with another equivalent of dppbz to afford [Ru(dppbz)2Cl2]. The two carbonyls and the two chlorides in [Ru(dppbz)(CO)2Cl2] could be displaced together by chelating mono-anionic bidentate ligands, viz. anions derived from 8-hydroxyquinoline (Hq) and 2-picolinic acid (Hpic) via loss of a proton, to afford the mixed-tris complexes [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], respectively. The molecular structures of four selected complexes, viz. [Ru(dppbz)(CO)(dmso)Cl2], [Ru(dppbz)2Cl2], [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], have been determined by X-ray crystallography. In dichloromethane solution, all the complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the complexes shows redox responses within 0.71 to -1.24 V vs. SCE. [Ru(dppbz)(CO)2Cl2] has been found to serve as an excellent pre-catalyst for catalytic transfer-hydrogenation and Oppenauer oxidation.