107-21-1 Usage
Chemical Description
Ethylene glycol is a diol that is commonly used as a coolant in automotive and industrial applications.
Chemical Description
Ethylene glycol is a colorless, odorless, and sweet-tasting liquid that is commonly used as a solvent and antifreeze.
Uses
Used in Automobile Industry:
Ethylene glycol is used as an antifreeze in heating and cooling systems, such as automobile radiators and coolant for airplane motors. It is also used in the hydraulic brake fluids, providing protection against freezing and corrosion.
Used in Chemical Industry:
Ethylene glycol serves as a raw material for the production of polyethylene terephthalate, which is used in the manufacturing of polyester fibers and plastic materials. It is also used in the production of synthetic resins, solvents, lubricants, surfactants, emollients, and moisturizers.
Used in Pharmaceutical Industry:
Ethylene glycol can be used as an alternative to glycerol and is often used as a hydration agent and solvent in the tanning industry and pharmaceutical industry.
Used in Paint and Plastics Industry:
Ethylene glycol is used as a solvent for paints, plastics, and inks, as well as a softening agent for cellophane.
Used in Firefighting:
Ethylene glycol is used as a stabilizing agent for soybean foam, which is used to extinguish oil and gasoline fires.
Used in Safety Explosives:
Ethylene glycol is used in the synthesis of safety explosives, glyoxal, unsaturated ester-type alkyd resins, plasticizers, elastomers, synthetic fibers (Terylene, Dacron), and synthetic waxes.
Used in Theatrical Applications:
Ethylene glycol is used to create artificial smoke and mist for theatrical purposes.
Used in Industrial Applications:
Ethylene glycol is used as an industrial humectant, an ingredient in electrolytic condensers (where it serves as a solvent for boric acid and borates), and in the formulation of printers' inks, stamp pad inks, and ball-point pen ink.
Used in Reagent Applications:
Ethylene glycol is used as a reagent typically in cyclocondensation reactions with aldehydes and ketones to form 1,3-dioxolanes.
Used in Hydraulic Fluids:
Ethylene glycol can be supplemented to hydraulic fluid to prevent the erosion of oil-based hydraulic fluid on the rubber of the system. The water-based hydraulic fluid with ethylene glycol as a main component is an inflammable hydraulic fluid and can be applied to the molding machine in aircraft, automobiles, and high-temperature operations.
Dihydric alcohol
Ethylene glycol is the simplest aliphatic dihydric alcohol with chemical properties of alcohols such as being capable of generating ether, ester, or being oxidized into acid or aldehyde as well as being condensed to form ether or being substituted by halogen. Its reaction with acyl chloride or acid anhydride generally forms di-esters. Under heating in the presence of catalyst (manganese dioxide, aluminum oxide, zinc oxide or sulfuric acid), it can be subject to intermolecular or intramolecular dehydration to form the cyclic ethylene acetals, which can react with nitric acid to generate glycol dinitrate (an explosive). Ethylene glycol is the raw material for production of polyester resins, alkyd resins and polyester fiber. It can also be used as the refrigerant agent for automobile and aircraft engines refrigerant. In 1980, the glycol amount used as refrigerant agent is equal to the amount consumption for producing polyester. In addition, it can also be used for synthesizing polymers such as polyester fibers. Ethylene glycol dinitrate, when used in combination with nitroglycerine can reduce the freezing point of explosives. Ethylene glycol can also be used as the raw material of pharmaceuticals and plastics and high-boiling solvents. Industry applied ethylene as a raw material with first converting it to ethylene oxide and then hydrolyzing to produce ethylene glycol.
This product is of fire and explosion hazards. It is irritating to skin and mucous membrane with inhalation of vapors or skin absorption producing a narcotic effect on the central nervous as well as causing kidney damage. Rat, through oral administration, has a LD50 of 8540 mg/kg. The maximal allowable concentration in the workplace is 5 × 10-6.
This information is edited by Xiongfeng Dai from lookchem.
Poisoning and first aid
This product is of low toxicity. Rat LD50: 5.5ml/kg~8.54ml/kg. People who is subject to oral administration by once has a LD50 of 80g~100g. The plasma concentration of ethylene glycol is 2.4g/L and can cause acute renal failure. It can be absorbed through the digestive tract, respiratory tract and skin. It can be discharged from the kidney in the form of prototype or ethanedioic acid (oxalate) from through oxidation. Glycol, after being oxidized into carbon dioxide, can be discharged from the respiratory tract.
Although ethylene glycol has a high toxicity but its volatility is small. Therefore, it is unlikely that the inhalation of it during production can cause severe poisoning. Inhalation poisoning is manifested as blurred consciousness, nystagmus and urine containing protein, calcium oxalate crystals and red blood cells. Oral toxicity in clinical practice can be divided into three stages: the first stage is mainly the central nervous system symptoms, such as the performance of ethanol poisoning; the second phase of the main symptoms mainly include shortness of breath, cyanosis, and various manifestations of pulmonary edema or bronchopneumonia; at the third stage, there may be significant renal disease, low back pain, kidney area percussion pain, renal dysfunction, proteinuria, hematuria, urine containing calcium oxalate crystals, as well as oliguria, anuria and even acute renal failure.
Patients mistakenly take it should be subject to the treatment based on the general principles of first aid for oral poisoning and can be given 600 mL of 1/6 mol of sodium lactate solution and 10 mL of 10% calcium gluconate through intravenous infusion. Patients of severe poisoning can subject to treatment of artificial kidney dialysis.
Container of ethylene glycol should have "toxic agents" mark. The product, upon heating, should be sealed, vented to prevent inhalation of the vapor or aerosol. Avoid long-term direct skin contact with the product.
Production method
1. Direct hydration of ethylene oxide is currently the only way for industrial-scale production of ethylene glycol. Ethylene oxide and water, under pressure (2.23MPa) and 190-200 ℃ conditions, and can directly have liquid-phase hydration reaction in a tubular reactor to generate ethylene glycol while being with byproducts diethylene glycol, tripropylene ethylene gl]ycol and multi-uret poly ethylene glycol. The dilute ethylene glycol solution obtained from the reaction further undergoes thin film evaporator condensation, and then dehydration, refinement to obtain qualified products and by-products. 2. sulfuric acid catalyzed hydration of ethylene oxide; ethylene oxide can react with water, in the presence of sulfuric acid as the catalyst, at 60-80 ℃ and pressure of 9.806-19.61kPa for hydration to generate ethylene glycol. The reaction mixture can be neutralized by liquid alkaline and evaporated of the water to obtain 80% ethylene glycol, and then distilled and concentrated in distillation column to obtain over 98% of the finished product. This method is developed in early time. Owing to the presence of corrosion, pollution and product quality problems, together with complex refining process, countries have gradually discontinued and instead change to direct hydration. 3. Direct ethylene hydration; directly synthesize ethylene glycol from ethylene instead of being via ethylene oxide. 4. dichloroethane hydrolysis. 5. Formaldehyde method.
Industrial preparation of ethylene glycol adopts chlorine ethanol method, ethylene oxide hydration and direct ethylene hydration with various methods having their characteristics, as described below.
Chlorohydrin method
Take chloroethanol as raw materials for hydrolysis in alkaline medium to obtain it. The reaction is carried out at 100 ℃. First generate ethylene oxide. Then pressurize at 1.01 MPa pressure to obtain ethylene glycol.
Ethylene oxide hydration
Hydration of ethylene oxide contains catalytic hydration and direct hydration. The hydration process can be carried out under either normal pressure or under compression. Normal pressure method generally take a small amount of inorganic acid as catalyst for reaction at 50~70 ℃.
Pressurized hydration had a high demand for the molar ratio of ethylene oxide over water which is higher than 1:6, to reduce the side reaction of producing the ether with the reaction temperature being at 150 °C and the pressure being 147kPa with hydration generating ethylene glycol.
There are currently gas phase catalytic hydration with silver oxide being the catalyst and the alumina oxide being the carrier for reaction at 150~240 ℃ to generate ethylene glycol.
Direct hydration of ethylene
Ethylene, in the presence of catalyst (e.g., antimony oxide TeO2 with palladium catalyst) can be oxidized in acetic acid solution to generate monoacetate ester or diacetate ester with further hydrolysis obtaining the ethylene glycol.
The above several methods takes ethylene oxide hydration as good with simple process and is suitable for industrialization.
Toxicity grading
Poisoning.
Acute toxicity
Oral-rat LD50: 4700 mg/kg; Oral-Mouse LD50: 5500 mg/kg.
Irritation data
Skin-rabbit 555 mg Mild; Eyes-rabbit 500 mg/24 hr mild.
Hazardous characteristics of explosive
Being mixed with air can be explosive.
Flammability and hazard characteristics
It is combustible in case of fire, high temperature and strong oxidant with burning releasing smoke irritation.
Storage characteristics
Treasury: ventilation, low-temperature and dry.
Extinguishing agents
Foam, carbon dioxide, water spray, sand.
Professional standards
TWA 60 mg/m3; STEL 120 mg/m3.
Production Methods
Historically, ethylene glycol has been manufactured by
hydrolyzing ethylene oxide. Presently, it is also produced
commercially by oxidizing ethylene in the presence of acetic
acid to form ethylene diacetate, which is hydrolyzed to the
glycol, and acetic acid is recycled in the process .
Preparation
Ethylene glycol is prepared by the hydration of ethylene oxide:
This reaction is carried out in a manner comparable to that described for the
preparation of propylene glycol from propylene oxide .
Ethylene glycol is a colourless liquid, b.p. 197°C.
Reactions
Glycol reacts (1) with sodium to form sodium glycol, CH2OH · CH2ONa, and disodium glycol, CH2ONa·CH2ONa; (2) with phosphorus pentachloride to form ethylene dichloride, CH2Cl·CH2Cl (3) with carboxy acids to form mono- and disubstituted esters, e.g., glycol monoacetate, CH2OH·CH2OOCCH3, glycol diacetate, CH3COOCH2 · CH2OOCCH3; (4) with nitric acid (with sulfuric acid), to form glycol mononitrate, CH2OH·CH2ONO2, glycol dinitrate, CH2ONO2 · CH2ONO2; (5) with hydrogen chloride, heated, to form glycol chlorohydrin (ethylene chlorohydrin, CH2OH·CHCl); (6) upon regulated oxidation to form glycollic aldehyde, CH2OH·CHO, glyoxal, CHO · CHO, glycollic acid, CH2OH·COOH, glyoxalic acid, CHO·COOH, oxalic acid, COOH·COOH.
Reactivity Profile
Mixing Ethylene glycol in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid, oleum, sulfuric acid, [NFPA 1991].
Hazard
Questionable carcinogen. Toxic by ingestion and inhalation. Lethal dose reported to be
100 cc.
Health Hazard
Inhalation of vapor is not hazardous. Ingestion causes stupor or coma, sometimes leading to fatal kidney injury.
Health Hazard
The acute inhalation toxicity of 1,2-ethanediolis low. This is due to its low vaporpressure, 0.06 torr at 20°C (68°F). Its saturationconcentration in air at 20°C (68°F)is 79 ppm and at 25°C (77°F) is 131 ppm(ACGIH 1986). Both concentrations exceedthe ACGIH ceiling limit in air, which is50 ppm. In humans, exposure to its mist orvapor may cause lacrimation, irritation ofthroat, and upper respiratory tract, headache,and a burning cough. These symptoms maybe manifested from chronic exposure toabout 100 ppm for 8 hours per day for severalweeks.The acute oral toxicity of 1,2-ethanediol islow to moderate. The poisoning effect, however,is much more severe from ingestionthan from inhalation. Accidental ingestion of80–120 mL of this sweet-tasting liquid canbe fatal to humans. The toxic symptoms inhumans may be excitement or stimulation,followed by depression of the central nervoussystem, nausea, vomiting, and drowsiness,which may, in the case of severe poisoning,progress to coma, respiratory failure, anddeath. When rats were administered sublethaldoses over a long period, there was depositionof calcium oxalate in tubules, causinguremic poisoning.LD50 value, oral (rats): 4700 mg/kgIngestion of 1,2-ethanediol produced reproductiveeffects in animals, causing fetotoxicity, postimplantation mortality, andspecific developmental abnormalities. Mutagenictests proved negative. It tested negativeto the histidine reversion–Ames test.
Fire Hazard
Ethylene glycol is combustible.
Flammability and Explosibility
Notclassified
Biochem/physiol Actions
Ethylene glycol is a low toxicity molecule and is used for embryo cryopreservation in many domestic animals.Ethylene glycol 5M solution is an additive screening solution of Additive Screening Kit. Additive Screen kit is designed to allow rapid and convenient evaluation of additives and their ability to influence the crystallization of the sample. The Additive Kit provides a tool for refining crystallization conditions.
Safety Profile
Human poison by
ingestion. (Lethal dose for humans reported
to be 100 mL.) Moderately toxic to humans
by an unspecified route. Moderately toxic
experimentally by ingestion, subcutaneous,
intravenous, and intramuscular routes.
Human systemic effects by ingestion and
inhalation: eye lachrymation, general
anesthesia, headache, cough, respiratory
stimulation, nausea or vomiting, pulmonary,
kidney, and liver changes. If ingested it
causes initial central nervous system
stimulation followed by depression. Later, it
causes potentially lethal kidney damage.
Very toxic in particulate form upon
inhalation. An experimental teratogen.
Other experimental reproductive effects.
Human mutation data reported. A skin, eye,
and mucous membrane irritant.
Combustible when exposed to heat or
flame; can react vigorously with oxidants. Moderate explosion hazard when exposed
to flame. Iptes on contact with chromium
trioxide, potassium permanganate, and
sodium peroxide. Mixtures with ammonium
dichromate, silver chlorate, sodium chlorite,
and uranyl nitrate ipte when heated to
100°C. Can react violently with
chlorosulfonic acid, oleum, H2SO4, HClO4,
and Pass. Aqueous solutions may ignite
silvered copper wires that have an applied
D.C. voltage. To fight fire, use alcohol foam,
water, foam, CO2, dry chemical. When
heated to decomposition it emits acrid
smoke and irritating fumes.
Potential Exposure
Ethylene glycol is used in antifreeze (especially as car radiator antifreeze) and in production of polyethylene terephthalate fibers and films; in hydraulic fluids; antifreeze and coolant mixtures for motor vehicles; electrolytic condensers; and heat exchangers. It is also used as a solvent and as a chemical intermediate for ethylene glycol dinitrate, glycol esters; resins, and for pharmaceuticals.
Environmental Fate
Ethylene glycol is considered an inert ingredient in pesticides. It
typically enters the environment through waste streams after
use of deicing products, where it is highly mobile in soil and
contaminates groundwater. Ethylene glycol is considered
‘readily biodegradable.’ It biodegrades relatively quickly; its
half-life (t1/2) is 2–12 days in soil.
Ethylene glycol is biodegraded in water under both aerobic
and anaerobic conditions within a day to a few weeks. In the
atmosphere, ethylene glycol photochemically degrades with
a t1/2 of approximately 2 days.
Shipping
UN3082 Environmentally hazardous substances,
liquid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required
Purification Methods
It is very hygroscopic, and also likely to contain higher diols. Dry it with CaO, CaSO4, MgSO4 or NaOH and distil it under vacuum. Dry further by reaction with sodium under nitrogen, reflux for several hours and distil. The distillate is then passed through a column of Linde type 4A molecular sieves and finally distil under nitrogen, from more molecular sieves. Then fractionally distil it. [Beilstein 1 IV 2369.]
Toxicity evaluation
Ethylene glycol has low toxicity but it is metabolized to
a variety of toxic metabolites. Ethylene glycol and glycolaldehyde
have an intoxicating effect on the central nervous
system that can lead to ataxia, sedation, coma, and respiratory
arrest similar to ethanol intoxication. However, the profound
metabolic acidosis reported in toxicity is secondary to accumulation
of acid metabolites, especially glycolic acid. The
oxalic acid metabolite complexes with calcium and precipitates
as calcium oxalate crystals in the renal tubules, leading to acute
renal injury. Further, oxalate’s ability to chelate calcium may
cause clinically relevant serum hypocalcemia.
Incompatibilities
Reacts with sulfuric acid, oleum, chlorosulfonic acid; strong oxidizing agents; strong bases; chromium trioxide; potassium permanganate; sodium peroxide.
Hygroscopic (i.e., absorbs moisture from the air)
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. Alternatively, ethylene glycol can be recovered
from polyester plant wastes
Check Digit Verification of cas no
The CAS Registry Mumber 107-21-1 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,0 and 7 respectively; the second part has 2 digits, 2 and 1 respectively.
Calculate Digit Verification of CAS Registry Number 107-21:
(5*1)+(4*0)+(3*7)+(2*2)+(1*1)=31
31 % 10 = 1
So 107-21-1 is a valid CAS Registry Number.
InChI:InChI=1/C2H4.2H2O/c1-2;;/h1-2H2;2*1H2
107-21-1Relevant articles and documents
Efficient conversion of microcrystalline cellulose to 1,2-alkanediols over supported Ni catalysts
Wang, Xicheng,Meng, Lingqian,Wu, Feng,Jiang, Yijun,Wang, Lei,Mu, Xindong
, p. 758 - 765 (2012)
Nickel supported on a variety of supports was evaluated in the batchwise hydrogenolysis of high-crystalline cellulose under hydrothermal conditions. The supports examined included Al2O3, kieselguhr, TiO 2, SiO2, activated carbon (AC), ZnO, ZrO2 and MgO. All tested catalysts can effectively convert cellulose while the choice of supports plays a critical role in the product distribution and selectivity. The Ni catalysts favour the formation of industrially attractive 1,2-alkanediols such as 1,2-propanediol, ethylene glycol, 1,2-butanediol and 1,2-hexanediol. It was found that the bifunctional ZnO-supported Ni catalysts displayed superior activities and the best result was obtained on 20% Ni/ZnO which exhibited complete conversion of cellulose with up to 70.4% total glycol yields. The mechanism of the reaction involved was tentatively proposed by identifying the products formed. The Royal Society of Chemistry 2012.
Cu-Mg-Zr/SiO2 catalyst for the selective hydrogenation of ethylene carbonate to methanol and ethylene glycol
Tian, Jingxia,Chen, Wei,Wu, Peng,Zhu, Zhirong,Li, Xiaohong
, p. 2624 - 2635 (2018)
A Cux-Mgy-Zrz/SiO2 catalyst with a total metal loading of 60 wt% prepared by a deposition-precipitation method was applied for the selective hydrogenation of ethylene carbonate to methanol and ethylene glycol in a fixed-bed reactor. As a result, the Cu8-Mg1-Zr0.47/SiO2 catalyst furnished 99% ethylene carbonate conversion with 85% selectivity to methanol and 99% selectivity to ethylene glycol under the optimized reaction conditions. Moreover, the Cu8-Mg1-Zr0.47/SiO2 catalyst also showed a good lifetime and neither the activity nor the selectivity decreased the during 208 h test. The reaction was found to depend sensitively on the Cu particle size, the surface acidity and the catalyst surface composition. The synergistic effect of balanced Cu0 and Cu+ sites was considered to play a critical role in attaining high yields of methanol and ethylene glycol. Boric oxide also had a positive effect on the hydrogenation of ethylene carbonate, affording higher selectivity to methanol under much milder conditions.
Hydrogenation of dimethyl oxalate to ethylene glycol over Cu/KIT-6 catalysts
Yu, Xinbin,Burkholder, Michael,Karakalos, Stavros G.,Tate, Gregory L.,Monnier, John R.,Gupton, B. Frank,Williams, Christopher T.
, p. 2403 - 2413 (2021)
Copper supported on KIT-6 mesoporous silica was preparedviaammonia evaporation (AE) method and applied for the catalytic hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG). The high specific surface area and interconnected mesoporous channels of the support facilitated the dispersion of copper species. The effect of AE temperature and copper loading on the structure of catalysts and induced change in hydrogenation performance were studied in detail. The results showed that both parameters influenced the overall and/or intrinsic activity. The hydrogenation of DMO to EG was proposed to proceedviathe synergy between Cu0and Cu+sites and catalysts with high surface Cu0/Cu+ratio exhibited high intrinsic activity in the investigated range.
Catalytic Hydrogenation of Cyclic Carbonates using Manganese Complexes
Kaithal, Akash,H?lscher, Markus,Leitner, Walter
, p. 13449 - 13453 (2018)
Catalytic hydrogenation of cyclic carbonates to diols and methanol was achieved using a molecular catalyst based on earth-abundant manganese. The complex [Mn(CO)2(Br)[HN(C2H4PiPr2)2] 1 comprising commercially available MACHO ligand is an effective pre-catalyst operating under relatively mild conditions (T=120 °C, p(H2)=30–60 bar). Upon activation with NaOtBu, the formation of coordinatively unsaturated complex [Mn(CO)2[N(C2H4PiPr2)2)] 5 was spectroscopically verified, which confirmed a kinetically competent intermediate. With the pre-activated complex, turnover numbers up to 620 and 400 were achieved for the formation of the diol and methanol, respectively. Stoichiometric reactions under catalytically relevant conditions provide insight into the stepwise reduction form the CO2 level in carbonates to methanol as final product.
One-pot synthesized core/shell structured zeolite@copper catalysts for selective hydrogenation of ethylene carbonate to methanol and ethylene glycol
Ding, Yu,Tian, Jingxia,Chen, Wei,Guan, Yejun,Xu, Hao,Li, Xiaohong,Wu, Haihong,Wu, Peng
, p. 5414 - 5426 (2019)
Copper-based catalysts, with highly dispersed and stabilized Cu nanoparticles, intensified mass transfer and a well-balanced Cu0/Cu+ ratio at low Cu loadings, are highly desirable for the selective hydrogenation of ethylene carbonate to ethylene glycol and methanol, an efficient indirect route of CO2 utilization. A hierarchically core/shell-structured Silicalite-1@Cu composite was developed via a base-assisted chemoselective host-guest interaction between the silicon species of MFI-type Silicalite-1 and external Cu salt source. In situ generated mesoporosity and strong Cu-silicate interaction made the uniform Cu NPs firmly immobilized and highly dispersed outside the core S-1 crystals. The S-1@Cu hybrid possessed the co-existing Cu0/Cu+ active species with a suitable ratio, and served as a highly active, selective and robust catalyst for selective ethylene carbonate hydrogenation, providing a lifetime >350 h together with >99% ethylene carbonate conversion, >99% ethylene glycol yield, and more importantly 93% methanol yield at a relatively low Cu loading of 21.4 wt%.
Highly efficient conversion of carbon dioxide catalyzed by polyethylene glycol-functionalized basic ionic liquids
Yang, Zhen-Zhen,Zhao, Ya-Nan,He, Liang-Nian,Gao, Jian,Yin, Zhong-Shu
, p. 519 - 527 (2012)
A series of polyethylene glycol (PEG)-functionalized basic ionic liquids (ILs) were developed for efficient CO2 conversion into organic carbonates under mild conditions. In particular, BrTBDPEG150TBDBr was proven to be a highly efficient and recyclable catalyst for the synthesis of cyclic carbonates without utilization of any organic solvents or additives. This is presumably due to the activation of epoxide assisted by hydrogen bonding and activation of CO2 by the ether linkage in the PEG backbone or through the formation of carbamate species with the secondary amino group in the IL cation on the basis of in situ FT-IR study under CO2 pressure. In addition, the subsequent transesterification of cyclic carbonate e.g. ethylene carbonate (EC) with methanol to dimethyl carbonate (DMC) can also be effectively catalyzed by BrTBDPEG150TBDBr, thanks to the activation of methanol by the secondary and tertiary nitrogen in the IL to easily form CH 3O-, realizing a so-called "one-pot two-stage" access to DMC from CO2 without separation of cyclic carbonate by using one kind of single component catalyst. Therefore, this protocol represents a highly efficient and environmentally friendly example for catalytic conversion of CO2 into value-added chemicals such as DMC by employing PEG-functionalized basic ILs as catalysts.
Aqueous phase reforming of glycerol using doped graphenes as metal-free catalysts
Esteve-Adell, Iván,Crapart, Bertrand,Primo, Ana,Serp, Philippe,Garcia, Hermenegildo
, p. 3061 - 3068 (2017)
Boron-doped graphene obtained by pyrolysis at 900°C of the boric acid ester of alginate was found to be the most active graphene among a series of doped and co-doped graphenes to promote the aqueous phase reforming of glycerol at 250°C. This reaction is of interest in the context of valorization of the aqueous wastes of carbohydrate syrups. Control experiments adding to undoped graphene 1 wt% of triphenylborane, tris(pentafluorophenyl)borane or bis(pinacolyl)diborane as models of possible boron atom types present in B-doped graphene, and boric acid that could be present in a residual amount after pyrolysis, show in all cases an increase in the catalytic activity of graphene. B-doped graphene has also activity for glucose aqueous phase reforming. B-doped graphene undergoes deactivation upon reuse, probably due to B leaching. The results show that graphenes are promising metal-free catalysts for aqueous phase reforming and are alternatives to those containing platinum.
Mechanistic aspects of the oxidative functionalization of ethane and ethanol by platinum(II) salts in aqueous medium. Role of platinum(II)-olefin and platinum(IV) - alkyl intermediates
Hutson, Alan C.,Lin, Minren,Basickes, Naomi,Sen, Ayusman
, p. 69 - 74 (1995)
The relative rate of C-H bond activation by the Pt(II) ion decreased in the order H-CH2CH3 > H-CH2CH2OH > H-CH(OH)CH3.The platinum(II)-ethylene complex, -, 1, was the key intermediate in the oxidation of ethane, ethanol, and diethyl ether to 1,2-ethanediol by platinum(II) in aqueous medium.In particular, the intermediacy of 1 in the oxidation of ethanol to 1,2-ethanediol and 2-chloroethanol was verified through labeling studies.In D2O, 1, upon oxidation with one of a number of oxidants, converted to 2-, 2. 2 in turn decomposed to a mixture of 1,2-ethanediol and 2-chloroethanol on heating.The rate conversion of 1 was a function of pH, the anions present, and the oxidant used.While the conversion of 1 to 2 involved a nucleophilic attack by water (or hydroxide ion), such a step was not observed in the absence of an oxidant.In basic D2O, the sequential replacement of Cl- by OD- in 1 occurred to successively form -, - and -.The process was reversed upon acidification.The species 2-, 3, appeared to be the source for the small quantities of hydroxy- and/or chloroacetaldehyde formed during the oxidation of 1. 3 was synthesized independently by the reaction of acetaldehyde with a mixture of PtCl42-, and PtCl62- in aqueous medium.When 1 was oxidized by Cl2 in CD3OD solution, the principal product was 2- 4, when a small amount of water was present, and CD3OCH2CH2OCD3 in the absence of water. Keywords: Platinum complex; C-H activation; Oxidation; Ethane; Ethylene; Ethanol
Efficient one-pot production of 1,2-propanediol and ethylene glycol from microalgae (Chlorococcum sp.) in water
Miao,Zhu,Wang,Tan,Wang,Liu,Kong,Sun
, p. 2538 - 2544 (2015)
The catalytic valorization of microalgae, a sustainable feedstock to alleviate dependence on fossil fuel and offset greenhouse gases emissions, is of great significance for production of biofuels and value-added chemicals from aquatic plants. Here, an interesting catalytic process is reported to convert microalgae (Chlorococcum sp.) into 1,2-propanediol (1,2-PDO) and ethylene glycol (EG) in water over nickel-based catalysts. The influences of reaction temperature, initial H2 pressure and reaction time on the product distribution were systematically investigated by using a batch reactor. Under optimal reaction conditions (at 250 °C for 3 h with 6.0 MPa of H2 pressure), microalgae were directly and efficiently converted over a Ni-MgO-ZnO catalyst and the total yield of polyols was up to 41.5%. The excellent catalytic activity was attributed to the smaller size and better dispersion of Ni particles on the MgO-ZnO supporter based on the characterization results as well as its tolerance to nitrogen-containing compounds. Besides, the reaction pathway was proposed based on the formation of reaction intermediates and the results of model compound conversion.
Hydrogenolysis of glycerol over supported bimetallic Ni/Cu catalysts with and without external hydrogen addition in a fixed-bed flow reactor
Cai, Fufeng,Pan, Donghui,Ibrahim, Jessica Juweriah,Zhang, Jun,Xiao, Guomin
, p. 172 - 182 (2018)
The role of high hydrogen pressure in the hydrogenolysis of glycerol to 1,2-propanediol has been studied extensively. Given the peculiar properties of hydrogen such as its inflammability and explosibility, the hydrogenolysis of glycerol without external hydrogen addition seems a more advantageous option. This study focuses on the conversion of glycerol to 1,2-propanediol over different supported bimetallic Ni/Cu catalysts in a fixed-bed flow reactor, using in situ hydrogen production and external hydrogen. Among the catalysts prepared, Ni/Cu/TiO2 catalyst was observed to efficiently catalyze the hydrogenolysis of glycerol to 1,2-propanediol under N2 pressure using 2-propanol as hydrogen source. This was due to the high Cu dispersion and Ni/Cu atomic ratio on the catalyst surface. However, the experimental results indicated that the effect of catalyst acid sites on glycerol hydrogenolysis was more noticeable when the reaction was performed under H2 pressure. The metal active sites of the catalyst played a significant role in the hydrogen production and also affected the glycerol hydrogenolysis with hydrogen produced from 2-propanol catalytic transfer hydrogenation (CTH) and glycerol aqueous phase reforming (APR). The stability study revealed that the Ni/Cu/TiO2 catalyst underwent serious deactivation during the hydrogenolysis of glycerol. The characterization results showed that the metal leaching and metal particles sintering were responsible for the catalyst deactivation when the glycerol hydrogenolysis was conducted using water as a solvent. However, the activity loss for reactions performed using 2-propanol as a solvent was mainly related to the metal particles sintering and the presence of adsorbed species on the catalyst surface.
