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METHYLAL

CAS Number: 109-87-5
EC Number: 203-714-2
Chemical formula: C3H8O2
IUPAC name: Dimethoxymethane

Methylal, also called dimethoxymethane, is a colorless flammable liquid with a low boiling point, low viscosity and excellent dissolving power.
Methylal has a chloroform-like odor and a pungent taste.
Methylal is the dimethyl acetal of formaldehyde.
Methylal is soluble in three parts water and miscible with most common organic solvents.

Synthesis and structure of Methylal:
Methylal can be manufactured by oxidation of methanol or by the reaction of formaldehyde with methanol.
In aqueous acid, methylal is hydrolyzed back to formaldehyde and methanol.

Due to the anomeric effect, methylal has a preference toward the gauche conformation with respect to each of the C–O bonds, instead of the anti conformation. Since there are two C–O bonds, the most stable conformation is gauche-gauche, which is around 7 kcal/mol more stable than the anti-anti conformation, while the gauche-anti and anti-gauche are intermediate in energy.

Since Methylal is one of the smallest molecules exhibiting this effect, which has great interest in carbohydrate chemistry, Methylal is often used for theoretical studies of the anomeric effect.

Applications of Methylal:
Industrially, Methylal is primarily used as a solvent and in the manufacture of perfumes, resins, adhesives, paint strippers and protective coatings.
Another application is as a gasoline-additive for increasing octane number. Methylal can also be used for blending with diesel.

Reagent in organic synthesis:
Another useful application of Methylal is to protect alcohols with a methoxymethyl (MOM) ether in organic synthesis.
This can be done using phosphorus pentoxide in dry dichloromethane or chloroform.
This is a preferred method to using chloromethyl methyl ether (MOMCl).
Alternatively, MOMCl can be prepared as a solution in a methyl ester solvent by reacting Methylal and an acyl chloride in the presence of a Lewis acid catalyst like zinc bromide:

MeOCH2OMe + RC(=O)Cl → MeOCH2Cl + RC(=O)(OMe)).

The solution of the reagent can be used directly without purification, minimizing contact with the carcinogenic chloromethyl methyl ether.
Unlike the classical procedure, which uses formaldehyde and hydrogen chloride as starting materials, the highly carcinogenic side product bis(chloromethyl) ether is not generated.

Consumer Uses of Methylal:
Methylal is used in the following products: coating products, air care products, lubricants and greases, fuels, washing & cleaning products, adhesives and sealants, biocides (e.g. disinfectants, pest control products), fillers, putties, plasters, modelling clay and polishes and waxes.
Other release to the environment of Methylal is likely to occur from: outdoor use and indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners).

Service life of Methylal:
Other release to the environment of Methylal is likely to occur from: outdoor use in long-life materials with high release rate (e.g. tyres, treated wooden products, treated textile and fabric, brake pads in trucks or cars, sanding of buildings (bridges, facades) or vehicles (ships)) and indoor use in long-life materials with high release rate (e.g. release from fabrics, textiles during washing, removal of indoor paints).

Methylal can be found in complex stuffs, with no release intended: machinery, mechanical appliances and electrical/electronic products (e.g. computers, cameras, lamps, refrigerators, washing machines).
Widespread uses by professional workers
Methylal is used in the following products: lubricants and greases, coating products, explosives, fuels, hydraulic fluids, laboratory chemicals, plant protection products, polymers and washing & cleaning products.

Methylal is used for the manufacture of:
Other release to the environment of Methylal is likely to occur from: outdoor use and indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners).

Widespread uses by professional workers of Methylal:
Methylal is used in the following products: lubricants and greases, coating products, explosives, fuels, hydraulic fluids, laboratory chemicals, plant protection products, polymers and washing & cleaning products.

Uses at industrial sites:
Methylal is used in the following products: fuels, hydraulic fluids, lubricants and greases, polymers, coating products, heat transfer fluids, laboratory chemicals, washing & cleaning products and extraction agents.

Methylal has an industrial use resulting in manufacture of another substance (use of intermediates).
Release to the environment of Methylal can occur from industrial use: in processing aids at industrial sites, of substances in closed systems with minimal release, as an intermediate step in further manufacturing of another substance (use of intermediates) and for thermoplastic manufacture.

Molar mass: 76.095 g·mol−1
Appearance: Colorless liquid
Odor: Chloroform-like
Density: 0.8593 g cm−3 (at 20 °C)

Melting point: −105 °C (−157 °F; 168 K)
Boiling point: 42 °C (108 °F; 315 K)
Solubility in water: 33% (20 °C)
Vapor pressure: 330 mmHg (20 °C)

Magnetic susceptibility (χ): −47.3·10−6 cm3/mol
XLogP3: 0.2
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 2

Rotatable Bond Count: 2
Exact Mass: 76.052429494
Monoisotopic Mass: 76.052429494
Topological Polar Surface Area: 18.5 Å²

Heavy Atom Count: 5
Complexity: 12.4
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0

Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes

Reagent in organic synthesis of Methylal:
Another useful application of Methylal is to protect alcohols with a methoxymethyl (MOM) ether in organic synthesis.
This can be done using phosphorus pentoxide in dry dichloromethane or chloroform.
This is a preferred method to using chloromethyl methyl ether (MOMCl).

Alternatively, MOMCl can be prepared as a solution in a methyl ester solvent by reacting Methylal and an acyl chloride in the presence of a Lewis acid catalyst like zinc bromide:
MeOCH2OMe + RC(=O)Cl → MeOCH2Cl + RC(=O)(OMe)).

General description of Methylal:
Methylal (Methylal, methylal) is a biodegradable dimethyl acetal.
Methylal can be synthesized by acid catalyzed condensation of formaldehyde with methanol.
Methylal is amphiphilic in nature with low viscosity, surface tension and boiling point.

Methylal is a flammable, highly volatile solvent with good dissolving power.
Methylal is considered as a potential alternative fuel and fuel additive due to its high oxygen content and its ability to enhance the combustion characteristics of diesel and petrol.
Methylals thermal diffusivity has been determined by photoacoustic method.
Analysis of the molecular structure of Methylal by electron diffraction technique shows that it has C2 symmetry with a gauche-gauche conformation.

Applications of Methylal:
Methylal (Formaldehyde dimethyl acetal) may be used in the synthesis of methoxymethyl (MOM) ethers.
Methylal may also be used as an external cross-linker to form microporous polymers.

Methylal, also called methylal, is a clear colorless flammable liquid with a low boiling point, low viscosity and an excellent dissolving power.
Methylal has a chloroform-like odor and a pungent taste.

Methylal is the dimethyl acetal of formaldehyde.
Methylal is soluble in three parts water and miscible with most common organic solvents.

Methylal can be manufactured by oxidation of methanol or by the reaction of formaldehyde with methanol.
In aqueous acid, Methylal is hydrolyzed back to formaldehyde and methanol.

Methylal is primarily used as a solvent and in the manufacture of perfumes, resins, adhesives, paint strippers and protective coatings.
Due to the anomeric effect, Methylal has a preference toward the gauche conformation around the C–O bonds, instead of the anti conformation.
Since Methylal is one of the smallest molecules exhibiting this effect, which has great interest in carbohydrate chemistry, Methylal is often used for theoretical studies of the anomeric effect.

Methylal, also called methylal, is a colorless flammable liquid with a low boiling point, low viscosity and excellent dissolving power.
Methylal has a chloroform-like odor and a pungent taste.
Methylal is the dimethyl acetal of formaldehyde.
Methylal is soluble in three parts water and miscible with most common organic solvents.

Applications of Methylal:
Methylal is a useful synthetic intermediate.
Methylal is used to synthesize the vinyl sulfide nine-membered macrocyclic moiety of griseoviridin.
Methylal is also used to prepare (-)-callystatin A.

Methylal or Methylal is a versatile chemical with applications in many industries such as paints, perfume, pharmacy, and fuel additives.
Methylal can be produced through the reaction of methanol and formaldehyde in the presence of acid catalysts or, directly, through the selective oxidation of methanol over catalysts with redox and acid functionalities.
In terms of sustainability, the so-called bio-methanol derived from syngas obtained via biomass gasification can be used in Methylal synthesis.
In this review article, we have condensed and classified the research outputs published over the past decade aimed at producing Methylal from methanol over different types of catalysts.

The majority of studies described the reaction of methanol to Methylal in a promising way using heterogeneous catalysts in the gas phase for the ease of product and catalyst recovery as well as suitability for continuous processing.
Likewise, the influence of parameters including catalyst component, feed composition, and temperature on the performance of catalysts utilised in Methylal production is analysed and discussed.
Further, some perspectives concerning the evolution of potential Methylal market with respect to the characteristics of the best catalyst materials for high Methylal productivity are expressed.

The present invention discloses a Methylal preparation process, wherein methanol and paraformaldehyde are adopted as raw materials, an acid is adopted as a catalyst, a reaction is performed in an organic solvent in an intermittent reaction manner under stirring to generate Methylal, and separation is performed to obtain the azeotrope of methanol and Methylal or the high-purity Methylal.
According to the present invention, the preparation process has characteristics of rapid reaction and high conversion rate, and is suitable for the organic chemical industry field.

Methylal is a low-boiling solvent, stable in the presence of alkalis and mild acids, and to high temperatures and pressures.
Methylal differs from other ethers in that it forms only minute omounts of peroxides.
Methylal will dissolve such synthetic resins as nitrocellulose, cellulose acetate and propionate, ethyl cellulose, vinyl, ''Epons'' and polystyrene, and also many of the natural gums and waxes.
Methylal as a latent solvent is activated by the addition of esters, ketones or alcohols.

Use and Manufacturing of Methylal:
In perfumery; manufacture of artificial resins; reaction medium for Grignard and Reppe reactions.
Methylal is a valuable extraction solvent for pharmaceutical products and a stable, inexpensive solvent for Grignard reactions.
Methylal is stable under alkaline and mild acidic conditions.

Chemical Properties of Methylal:
Methylal is a low-boiling solvent, stable in the presence of alkalis and mild acids, and to high temperatures and pressures.
Methylal differs from other ethers in that it forms only minute omounts of peroxides.
Methylal will dissolve such synthetic resins as nitrocellulose, cellulose acetate and propionate, ethyl cellulose, vinyl, "Epons" and polystyrene, and also many of the natural gums and waxes.
Methylal as a latent solvent is activated by the addition of esters, ketones or alcohols.
Methylals evaporation rate, twice that of acetone, places this ether in a class with such solvents as acetone, methyl acetate and ethyl acetate in resin formulations.

Reactivity Profile of Methylal:
Methylal, an acetal, is incompatible with strong oxidizing agents and acids .
Breaks down to formaldehyde and methanol in acidic solutions.
A very dangerous fire hazard when exposed to heat, flame or oxidizing agents.
May ignite or explode if heated with oxygen [Lewis].

Hazard:
Flammable, dangerous fire and explosion risk.
Toxic by ingestion and inhalation.
Eye irritant and central nervous system impairment.

Health Hazard of Methylal:
VAPOR: Irritating to eyes, nose and throat.
Harmful if inhaled.
LIQUID: Irritating to skin and eyes.
Harmful if swallowed.

Fire Hazard of Methylal:
FLAMMABLE.

Irritating gases may be produced when heated.
Containers may explode in fire.
Flashback along vapor trail may occur.
Vapor may explode if ignited in an enclosed area. Irritating formaldehyde gas may be present in smoke.

Chemical Reactivity of Methylal:
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.

Safety Profile of Methylal:
Moderately toxic by subcutaneous route.
Mildly toxic by ingestion and inhalation.
Can cause injury to lungs, liver, kidneys, and the heart.
A narcotic and anesthetic in high concentrations.

A very dangerous fire hazard when exposed to heat, flame, or oxidzers.
Moderately explosive when exposed to heat or flame.
May ignite or explode when heated with oxygen.
To fight fire, use foam, CO2, dry chemical.
When heated to decomposition it emits acrid smoke and irritating fumes.

Potential Exposure:
Vapors may form explosive mixture with air.
Methylal may be able to form unstable and explosive peroxides.
Heating may cause explosion.

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions.
Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.
Hydrolyzes readily in presence of acids to generate aldehydes.

Source:
Methylal is a by-product in the synthesis of trioxane, an intermediate in the manufacture of polyacetal plastics.

Purification Methods of Methylal:
Methylal is a volatile flammable liquid which is soluble in three parts of H2O, and is readily hydrolysed by acids.
Purify Methylal by shaking with an equal volume of 20% aqueous NaOH, stand for 20minutes, dry over fused CaCl2, filter and fractionally distil it through an efficient column.
Store Methylal over molecular sieves.

Methylal, a promising synthetic fuel enabling clean combustion, is usually produced by condensation of methanol and formaldehyde, where the latter stems from methanol oxidation. Here, we report the hydrogen efficient non-oxidative Methylal synthesis over a bifunctional Cu/zeolite catalyst in a continuous gas-phase fixed bed reactor.

Methanol dehydrogenation to formaldehyde (FA) is coupled with FA condensation with methanol to yield Methylal, hydrogen and water. Thermodynamic analysis confirms the general feasibility of this route and also manifests the vital importance of catalyst selectivity.
Therein, close proximity of the catalyst's metallic Cu species and acidic sites is crucial

Noticeably, Methylal selectivity of the catalyst only evolves within the first 13 hours of operation rising from 5.8 to 77.2%. A maximum Methylal selectivity of 89.2 or 80.3% could be reached for 0.4 and 0.7 wt% Cu on Hβ(836) zeolite with 1.9 or 3.6% methanol conversion, respectively.

Comprehensive characterizations emphasize adaptation of Cu species and Hβ zeolite under reaction conditions resulting in the decisive weakened dehydrogenation and condensation ability for high Methylal selectivity.
Process simulations confirm superior exergy efficiency compared to state-of-the-art technologies for Methylal production already with the herein developed catalyst and highlights the high potential of further innovations for technical implementation.

Methylal is a useful synthetic intermediate.
Methylal is used to synthesize the vinyl sulfide nine-membered macrocyclic moiety of griseoviridin.
Methylal is also used to prepare (-)-callystatin A.

Mainly used in the production of anion exchange resin, also used as a solvent and special fuel.
Methylal is also used in the manufacture of perfumes, the production of artificial resins, as a reaction medium for Grignard reactions and rapamycin (synthesis) reactions.

Other names:
1,1-dimethoxymethane
109-87-5
1697025
1O1O1
203-714-2
bis(methoxy)methane
dimethyl formal
Formaldehyde dimethyl acetal
formaldehyde dimethyl ketal
methylene dimethyl ether
(CH3O)2CH2
2,4-Dioxapentane
7H1M4G2NUE
anesthenyl
bis(methyloxy)methane
Formaldehyde methyl ketal
methylene glycol dimethylether
Methylenedioxydimethane
MFCD00008495
PA8750000
UN 1234
UNII-7H1M4G2NUE
109-87-5
Formal
Methane, dimethoxy-
Formaldehyde dimethyl acetal
Dimethyl formal
Anesthenyl
2,4-Dioxapentane
Methylene dimethyl ether
Bis(methoxy)methane
Methoxymethyl methyl ether
Metylal
Formaldehyde methyl ketal
Formaldehyde dimethylacetal
bis(methyloxy)methane
Methylene glycol dimethylether
7H1M4G2NUE
CHEBI:48341
Dimethoxy methane
HSDB 1820
EINECS 203-714-2
UN1234
UNII-7H1M4G2NUE
Dimethylformal
AI3-16096
CCRIS 9397
Methylene Glycol Dimethyl Ether
Dimethoxy-Methane
Methylenedioxydimethane
Dimethylacetal formaldehyde
(CH3O)2CH2
DTXSID1025564
ZINC2005853
MFCD00008495
AKOS000120977
ZINC112926527
UN 1234
D0637
FT-0625028
Q411496
J-520340
F0001-0207