METHANESULFONIC ACID (MSA)

Methanesulfonic acid (MSA) colorless liquid with the molecular formula CH3SO3H and structure H3C−S(=O)2−OH.
Methanesulfonic acid (MSA) is the simplest of the alkylsulfonic acids (R−S(=O)2−OH).
Salts and esters of Methanesulfonic acid (MSA) are known as mesylates (or methanesulfonates, as in ethyl methanesulfonate).
Methanesulfonic acid (MSA) is hygroscopic in its concentrated form.
Methanesulfonic acid (MSA) can dissolve a wide range of metal salts, many of them in significantly higher concentrations than in hydrochloric acid (HCl) or sulfuric acid (H2SO4).

CAS Number: 75-75-2
EC Number: 200-898-6
IUPAC Name: Methanesulfonic acid
Molecular Formula: CH3SO3H

Other names: METHANESULFONIC ACID, 75-75-2, Methylsulfonic acid, Methanesulphonic acid, Mesylic acid, Methanesulfonicacid, Sulfomethane, NSC 3718, CCRIS 2783, HSDB 5004, EINECS 200-898-6, METHANE SULFONIC ACID, BRN 1446024, DTXSID4026422, MSA, UNII-12EH9M7279, CHEBI:27376, AI3-28532, NSC-3718, CH3SO3H, MFCD00007518, 12EH9M7279, DTXCID806422, NSC3718, EC 200-898-6, 4-04-00-00010 (Beilstein Handbook Reference), J1.465F, ammoniummethanesulfonate, CH4O3S, vMsOH, 03S, MeSO3H, LACTIC ACID(DL), CH3SO2OH, H3CSO3H, WLN: WSQ1, CHEMBL3039600, Tox21_201073, AKOS009146947, AT25153, CAS-75-75-2, NCGC00248914-01, NCGC00258626-01, BP-12823, FT-0628287, M0093, M2059, NS00004472, EN300-29198, A934985, Q414168, J-521696, Methanesulfonic acid, Vetec(TM) reagent grade, 98%, F1908-0093, Z281776238, InChI=1/CH4O3S/c1-5(2,3)4/h1H3,(H,2,3,4

History and manufacturing of Methanesulfonic acid (MSA):
The first commercial production of Methanesulfonic acid (MSA), developed in the 1940s by Standard Oil of Indiana, was based on oxidation of dimethylsulfide by O2 from air.
Although inexpensive, this process suffered from a poor product quality and explosion hazards.

In 1967, the Pennwalt Corporation (USA) developed a different process for dimethylsulfide (as an water-based emulsion) oxidation using chlorine, followed by extraction-purification.
In 2022 this chlorine-oxidation process was used only by Arkema (France) for making high-purity Methanesulfonic acid (MSA).
This process is not popular on a large scale, because it co-produces large quantities of hydrochloric acid.

Between years 1970 and 2000 Methanesulfonic acid (MSA) was used only on a relatively small-scale in niche markets (for example, in the microelectronic and electroplating industries since the 1980s), which was mainly due to its rather high price and limited availability.
However, this situation changed around 2003, when BASF launched commercial production of Methanesulfonic acid (MSA) in Ludwigshafen based on a modified version of the aforementioned air oxidation process, using dimethyldisulfide instead of dimethylsulfide.

The former is produced in one step from methanol from syngas, hydrogen and sulfur.
An even better (lower-cost and environmentally friendlier) process of making Methanesulfonic acid (MSA) was developed in 2016 by Grillo-Werke AG (Germany).
It is based on a direct reaction between methane and oleum at around 50 °C and 100 bar in the presence of a potassium persulfate initiator.
This technology was acquired and commercialized by BASF in 2019

Applications of Methanesulfonic acid (MSA):
Since ca. 2000 Methanesulfonic acid (MSA) has become a popular replacement for other acids in numerous industrial and laboratory applications, because:

Methanesulfonic acid (MSA) is a strong acid.
Methanesulfonic acid (MSA) has a low vapor pressure.
Methanesulfonic acid (MSA) is not an oxidant or explosive, like nitric, sulfuric or perchloric acids.
Methanesulfonic acid (MSA) is a liquid at room temperature.

Methanesulfonic acid (MSA) is soluble in many organic solvents.
Methanesulfonic acid (MSA) forms water-soluble salts with all inorganic cations and with most organic cations.
Methanesulfonic acid (MSA) does not form complexes with metal ions in water.
Methanesulfonic acid (MSA)'s anion, mesylate, is non-toxic and suitable for pharmaceutical preparations.
The closely related p-toluenesulfonic acid (PTSA) is solid.

Methanesulfonic acid (MSA) can be used in the generation of borane (BH3) by reacting Methanesulfonic acid (MSA) with NaBH4 in an aprotic solvent such as THF or DMSO, the complex of BH3 and the solvent is formed.

Methanesulfonic acid (MSA) is also a primary ingredient in rust and scale removers.
Methanesulfonic acid (MSA) is used to clean off surface rust from ceramic, tiles and porcelain which are usually susceptible to acid attack.

Appearance: Clear, colourless liquid
Density: 1.48 g/cm3
Melting point: 17 to 19 °C

Boiling point: 167 °C
Solubility in water: miscible
Molecular Weight: 96.11 g/mol
XLogP3-AA: -0.9

Hydrogen Bond Donor Count: 1
Hydrogen Bond Acceptor Count: 3
Rotatable Bond Count: 0
Exact Mass: 95.98811516 g/mol

Monoisotopic Mass: 95.98811516 g/mol
Topological Polar Surface Area: 62.8Å²
Heavy Atom Count: 5
Complexity: 92.6

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

Consumer Uses of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) is used in the following products: washing & cleaning products, air care products, anti-freeze products and lubricants and greases.
Other release to the environment of Methanesulfonic acid (MSA) is likely to occur from: indoor use as processing aid and outdoor use as processing aid.

Widespread uses of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) is used in the following products: metal surface treatment products, pH regulators and water treatment products and laboratory chemicals.
Methanesulfonic acid (MSA) is used in the following areas: formulation of mixtures and/or re-packaging, health services and scientific research and development.
Methanesulfonic acid (MSA) is used for the manufacture of: fabricated metal products.
Release to the environment of Methanesulfonic acid (MSA) can occur from industrial use: in processing aids at industrial sites.
Other release to the environment of Methanesulfonic acid (MSA) is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners), outdoor use and indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters).

Formulation:
Methanesulfonic acid (MSA) is used in the following products: metal surface treatment products.
Release to the environment of Methanesulfonic acid (MSA) can occur from industrial use: formulation of mixtures, in processing aids at industrial sites, manufacturing of the substance, as an intermediate step in further manufacturing of another substance (use of intermediates), in the production of articles, as processing aid, as processing aid and of substances in closed systems with minimal release.

Uses at industry:
Methanesulfonic acid (MSA) is used in the following products: metal surface treatment products, pH regulators and water treatment products and laboratory chemicals.
Methanesulfonic acid (MSA) is used in the following areas: formulation of mixtures and/or re-packaging.
Methanesulfonic acid (MSA) is used for the manufacture of: chemicals.
Release to the environment of Methanesulfonic acid (MSA) can occur from industrial use: in processing aids at industrial sites, as processing aid, as an intermediate step in further manufacturing of another substance (use of intermediates), formulation of mixtures and in the production of articles.

Methanesulfonic acid (MSA) is a strong organic acid.
The chemical oxidation of dimetyl sulfide in the atmosphere leads to the formation of Methanesulfonic acid (MSA) in large quantities.
Methanesulfonic acid (MSA) undergoes biodegradation by forming CO2 and sulphate.
Methanesulfonic acid (MSA) is considered a green acid as Methanesulfonic acid (MSA) is less toxic and corrosive in comparison to mineral acids.
The aqueous Methanesulfonic acid (MSA) solution has been considered a model electrolyte for electrochemical processes.

Applications of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) may be used:
Methanesulfonic acid (MSA) is used as a catalyst to produce linear alkylbenzenes by the addition reaction between long-chain olefins and benzene.
Methanesulfonic acid (MSA) is used to prepare polyaniline (PANI)/graphene composites with enhanced thermal and electrical properties.
Methanesulfonic acid (MSA) is used as a catalyst for the transformation of glucose/xylose mixtures to levulinic acid and furfural.

Methanesulfonic acid (MSA) finds application in Pharmaceutical & Agrochemical synthesis.
Methanesulfonic acid (MSA) is used as Solvent and is also used as catalyst in Esterification, Polymerisation and Alkylation Reactions.
Methanesulfonic acid (MSA) can be used as excellent eco-friendly cleaning agent in house hold and industrial cleaners.
Methanesulfonic acid (MSA) also find application in Electroplating and Metal Surface Treatment.
Methanesulfonic acid (MSA) is also an excellent Rust & Scale removing agent.

Methanesulfonic acid (MSA) is used as an acid catalyst in organic reactions because Methanesulfonic acid (MSA) is a non-volatile, strong acid that is soluble in organic solvents.
Methanesulfonic acid (MSA) is convenient for industrial applications because Methanesulfonic acid (MSA) is liquid at ambient temperature, while the closely related p-toluenesulfonic acid (PTSA) is solid.
However, in a laboratory setting, solid PTSA is more convenient.
Methanesulfonic acid (MSA) can be used in the generation of borane (BH3).
By reacting Methanesulfonic acid (MSA) with NaBH4 in an aprotic solvent such as THF or DMS, the complex of BH3 and the solvent is formed.

Methanesulfonic acid (MSA) is considered a particularly suitable supporting electrolyte for electrochemical applications, were stands as an environmentally friendly alternative to other acid electrolytes used in plating processes.
Methanesulfonic acid (MSA) is also the electrolyte of choice in zinccerium (see cerium(III) methanesulfonate) and lead-acid (methanesulfonate)flow batteries.
Methanesulfonic acid (MSA) is used as a catalyst to produce linear alkylbenzenes by the addition reaction between long-chain olefins and benzene.

Methanesulfonic acid (MSA) (MsOH) or methanesulphonic acid (in British English) is a colorless liquid with the chemical formula CH3SO3H.
Methanesulfonic acid (MSA) is the simplest of the alkylsulfonic acids.
Salts and esters of Methanesulfonic acid (MSA) are known as mesylates (or methanesulfonates, as in ethyl methanesulfonate).
Methanesulfonic acid (MSA) is hygroscopic in its concentrated form.

Methanesulfonic acid (MSA) may be considered an intermediate compound between sulfuric acid (H2SO4), and methylsulfonylmethane ((CH3)2SO2), effectively replacing an –OH group with a –CH3 group at each step.
This pattern can extend no further in either direction without breaking down the –SO2– group.
Methanesulfonic acid (MSA) can dissolve a wide range of metal salts, many of them in significantly higher concentrations than in hydrochloric or sulfuric acid.

Methanesulfonic acid (MSA), the simplest alkanesulfonic acid, is a hygroscopic colorless liquid or white solid, depending on whether the ambient temperature is greater or less than 20 ºC.
Methanesulfonic acid (MSA) is very soluble in water and oxygenated solvents, but sparingly soluble in most hydrocarbons.
In aqueous solution, Methanesulfonic acid (MSA) is a strong acid (completely ionized).
Methanesulfonic acid (MSA)’s acidity and solubility properties make Methanesulfonic acid (MSA) industrially valuable as a catalyst in organic reactions, particularly polymerization.
In many applications, Methanesulfonic acid (MSA)s advantage over concentrated sulfuric acid is that Methanesulfonic acid (MSA) has similar acid strength but is not an oxidant.

Methanesulfinic acid is an important intermediate in the oxidation of dimethyl sulfide (DMS) in the marine boundary layer.
The oxidation of Methanesulfinic acid by ozone in the gas phase to form Methanesulfonic acid (MSA) was investigated using theoretical calculations in this paper.
Three pathways can be found for the reaction of MSIA with ozone.
The highest energy barrier is 13.02 kcal mol−1 in the most favorable pathway.

By comparing the reaction rate of MSIA + O3 with that of MSIA + OH, Methanesulfonic acid (MSA) can be concluded that the oxidation of MSIA by O3 to form Methanesulfonic acid (MSA) is of minor significance relative to Methanesulfonic acid (MSA)s oxidation by OH radical in the gas phase.
This study can provide some information for the theoretical and experimental studies in the significantly heterogeneous and aqueous-phase oxidation of MSIA by O3.

Methanesulfonate electroplating solution
Methanesulfonic acid (MSA) is a caustic chemical, briefly referred to as Methanesulfonic acid (MSA).
Methanesulfonic acid (MSA) has broad application prospect in the field of electroplating and has proved to be an excellent alternative of fluoride boric acid or phenolsulfonic acid.
Methanesulfonate electroplating solution has been applied to tin and tin-lead alloy plating, the product features are as follows:

The bright pure tin electroplating of the Methanesulfonic acid (MSA) type with the coating crystal being meticulous, even and exhibiting bright silver-white.
Methanesulfonic acid (MSA) has excellent weldability, being suitable in the electronics profession.
The plating solution has a high plating rate, a wide range of current density, faster deposition rate, and excellent deep plating capacity.
After the standard aging test or long-term storage, Methanesulfonic acid (MSA) can still maintain good welding performance.
Methanesulfonic acid (MSA) contains no fluorine boric acid with easy wastewater treatment, low corrosion, being environmentally friendly.

Chemical properties of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) appears as colorless or slightly brown oily liquid, appearing as solid at low temperatures.
Methanesulfonic acid (MSA) has a melting temperature of 20 °C, the boiling point of 167 °C (13.33 kPa), 122 °C (0.133 kPa), the relative density of 1.4812 (18 ℃) and refractive index 1.4317 (16 ℃).
Methanesulfonic acid (MSA) is soluble in water, alcohol and ether, insoluble in alkanes, benzene and toluene.
Methanesulfonic acid (MSA) will not subject to decomposition in boiling water and hot alkaline solution.
Methanesulfonic acid (MSA) also has strong corrosion effect against the metal iron, copper and lead.

Uses of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) is a raw material for medicine and pesticide.
Methanesulfonic acid (MSA) can also be used as dehydrating agent, curing accelerator for coating, treating agent for fiber, solvent, catalysis, and esterification as well as polymerization reaction.
Methanesulfonic acid (MSA) can be used as solvent, alkylation, catalyst of esterification and polymerization, also used in medicine and electroplating industry.
Methanesulfonic acid (MSA) can also be applied to oxidation.

Production method of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) can be obtained through the nitrate oxidation of thiocyanate methyl.
Nitric acid and negative water are heated carefully to 80-88 °C with fractional addition of methyl thiocyanate and the temperature being automatically rose to about 105 ℃.
After the reaction becomes mild, the reaction was heated to 120 ° C and reacted for 5 hours to obtain a crude product.

The crude product was diluted with exchanged water and adjusted to pH 8-9 by addition of 25% barium hydroxide solution and filtered.
The filtrate is condensed to until crystalline precipitation.
The crystal is washed by methanol to remove the nitrate to obtain the barium methanesulfonate.

Methanesulfonic acid (MSA) is then added to the exchanged water to boiling, add sulfuric acid for decomposition while Methanesulfonic acid (MSA) is hot, filter and the filtrate was concentrated under vacuum to no water to obtain the finished product.
Another method is that the methyl isothiourea sulfate is successively subject to chlorination, oxidation and hydrolysis to derive the finished product.

Methyl isothiourea sulfate was added to the water; and the chlorine is sent into at 20-25 ° C to until phenomenon such as solution color is turned into yellow; oil layer emerges in the bottom of the bottle; the temperature drop and large number of residual chlorine is discharged from the exhaust pipe; this indicates the end point of the reaction.

The reaction solution was extracted with chloroform.
After drying, the extract was distilled at 60-62 ° C under normal pressure to remove the chloroform, and then further subject to distillation under reduced pressure.
Collect the 60-65 °C (2.67 kPa) fraction was to obtain the methanesulfonyl chloride.

Add the base drop wise under stirring to 80 ℃ hot water and maintain the heat hydrolysis for about 2h, to until the reaction liquid droplets completely disappear.
The reaction solution was concentrated under reduced pressure to a syrupy form, diluted with water, and concentrated under reduced pressure to until no more water was distilled off to obtain Methanesulfonic acid (MSA).

Chemical Properties of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) is a colourless or light yellow liquid having a melting point of 20° C, is a strong acid acting corroding but not oxidizing.
Methanesulfonic acid (MSA) is used in the electroplating industry and for organic syntheses, in particular as a catalyst for alkylations, esterifications, and polymerizations.
Beyond that, Methanesulfonic acid (MSA) is used as a starting material for the preparation of methanesulfonyl chloride.

Uses of Methanesulfonic acid (MSA):
Polymerization catalyst.
Methanesulfonic acid (MSA) has been developed as an esterification catalyst in place of sulfuric acid for the synthesis of resins in paints and coatings.
One of the major advantages of Methanesulfonic acid (MSA) over sulfuric acid is that Methanesulfonic acid (MSA) is not an oxidizing species.

Preparation of Methanesulfonic acid (MSA):
Methanesulfonic acid (MSA) is produced predominantly by oxidizing methylthiol or dimethyl disulfide using nitric acid, hydrogen peroxide, chlorine or by employing electrochemical processes.

Physical properties of Methane Sulphoic Acid
Methane sulphonic acid is a clear colourless liquid available as a 70% solution in water and anhydrous form.
The structure of methane sulphonic acid lends itself to many catalytic reactions, due to Methanesulfonic acid (MSA)s high acid strength (pKa= -1.9) and low molecular weight (96.0 g/mol).

Methane Sulphonic Acid is Green Acid Catalysts
Methanesulfonic acid (MSA) is easy to handle methane sulphonic acid as liquid and can be recyclized.
Methanesulfonic acid (MSA) has low LD50 and biodegradable forming sulphate and CO2.
Methane sulphonic acid is considered to be natural product and is part of the natural sulphur.
Methanesulfonic acid (MSA) is less corrosive and toxic than other mineral acids.
Due to these properties methane sulphonic acid making an environmentally benign material.

Applications
Methanesulfonic acid (MSA) is used as an acid catalyst in organic reactions because Methanesulfonic acid (MSA) is a non-volatile, strong acid that is soluble in organic solvents.
Methanesulfonic acid (MSA) is convenient for industrial applications because Methanesulfonic acid (MSA) is liquid at ambient temperature, while the closely related p-toluenesulfonic acid (PTSA) is solid.
However, in a laboratory setting, solid PTSA is more convenient.
Methanesulfonic acid (MSA) can be used in the generation of borane (BH3) by reacting Methanesulfonic acid (MSA) with NaBH4 in an aprotic solvent such as THF or DMS, the complex of BH3 and the solvent is formed.

Electroplating
Solutions of Methanesulfonic acid (MSA) are used for the electroplating of tin and tin-lead solders.
Methanesulfonic acid (MSA) is displacing the use of fluoroboric acid, which releases corrosive and volatile hydrogen fluoride.
Methanesulfonic acid (MSA) is also a primary ingredient in rust and scale removers.
Methanesulfonic acid (MSA) is used to clean off surface rust from ceramic, tiles and porcelain which are usually susceptible to acid attack.

Methanesulfonic acid (MSA) was used as catalyst for the electrophilic addition of long-chain olefins such as 1-dodecene to benzene.
The influence of the temperature, the ratios of the reactants, the amount of Methanesulfonic acid (MSA), and the stirring of the reaction mixture were investigated.
After a 3 h reaction time at 80 °C, a selectivity to the phenyldodecanes of more than 90% was obtained at 98% dodecene conversion.

Methanesulfonic acid (MSA) could be recycled at least five times after a treatment with water and dichloromethane and a subsequent water removal.
The presence of water in the reaction mixture was found to be detrimental for the activity of Methanesulfonic acid (MSA).
The inhibitory products formed during the reaction, as well as the crude organic phase, have been proved also as responsible for Methanesulfonic acid (MSA) deactivation.
This method represents an environmentally benign alkylation route, because Methanesulfonic acid (MSA) could easily be separated from the reaction mixture via decantation and because Methanesulfonic acid (MSA) could be reused.
In addition to that, Methanesulfonic acid (MSA) is biodegradable.

Methane sulphonic acid, also known as Methanesulfonic acid (MSA) or mesylic acid.
Methanesulfonic acid (MSA) is widely used as an acid catalyst and solvent in organic reactions in biological and agricultural industry.
Methanesulfonic acid (MSA) is also a key ingredient in plating various metals to print circuit board manufacture in electric industry.
Besides, Methane sulphonic acid is popularly used in textile treatment, and the production of plastics and polymers.

Methanesulfonic acid (MSA) is one of the major organosulfur acids formed from the photochemical oxidation of dimethyl sulfide (DMS) produced by oceanic phytoplankton.
Methanesulfonic acid (MSA) can react with metal halides (e.g. sodium chloride) in ambient aerosols to form methanesulfonate salts (e.g. sodium methanesulfonate, CH3SO3Na).
While the formation processes of Methanesulfonic acid (MSA) and Methanesulfonic acid (MSA)s salts are reasonably well understood, their subsequent chemical transformations in the atmosphere are not fully resolved.
Methanesulfonic acid (MSA) and Methanesulfonic acid (MSA)s salts accumulate near the aerosol surface due to their surface activities, which make them available to heterogeneous oxidation at the gas-aerosol interface by oxidants such as hydroxyl (OH) radicals.

In this work, the compositional changes of aerosol comprised of Methanesulfonic acid (MSA) and Methanesulfonic acid (MSA)s sodium salt (CH3SO3Na) are measured following heterogeneous OH oxidation.
An aerosol flow tube reactor is coupled with a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART) and a high-resolution mass spectrometer at a relative humidity (RH) of 90 %.
Aerosol mass spectra reveal that Methanesulfonic acid (MSA) and CH3SO3Na can be detected as methanesulfonate ion (CH3SO3⁻) with minimal fragmentation in the negative ionization mode.

Kinetic measurements show that OH oxidation with Methanesulfonic acid (MSA) and CH3SO3Na has an effective OH uptake coefficient of 0.45 ± 0.14 and 0.20 ± 0.06, respectively, revealing that Methanesulfonic acid (MSA) reacts with OH radical faster than Methanesulfonic acid (MSA)s sodium salt.
One possibility for the difference in reactivity of these two compounds is that CH3SO3Na is more hygroscopic than Methanesulfonic acid (MSA).
The increase in the coverage of water molecules at the surface of CH3SO3Na might reduce the reactive collision probability between CH3SO3⁻ and OH radicals, resulting in a smaller reaction rate.

Methanesulfonic acid (MSA) and CH3SO3Na dissociate to form CH3SO3⁻, which tends to fragment into formaldehyde (HCHO) and a sulfite radical (SO3•−) upon oxidation.
Formaldehyde partitions back to the gas phase owing to Methanesulfonic acid (MSA)s high volatility, and SO3•− can initiate a series of chain reactions involving various inorganic sulfur radicals and ions in the aerosol phase.
Overall, the fragmentation and SO3•−-initiated chemistry are the major processes controlling the chemical evolution of Methanesulfonic acid (MSA) and Methanesulfonic acid (MSA)s sodium salt aerosols during heterogeneous OH oxidation.

Methanesulfonic acid (MSA) is a strong organic acid used in numerous applications ranging from chemical and biofuel synthesis to industrial cleaning and metal surface treatment in the electronics industry.
The expansion is in line with the trend for top-performance and at the same time environmentally friendly technologies in various industries.
BASF’s proprietary process enables the production of Methanesulfonic acid (MSA) – a high-purity Methanesulfonic acid (MSA).
Lutropur Methanesulfonic acid (MSA) is a sustainable alternative to other acids such as sulfuric, phosphoric or acetic acid.
As part of the natural sulfur cycle Methanesulfonic acid (MSA) is readily biodegradable.
Further benefits in practical applications come, for example, from Methanesulfonic acid (MSA)s nonoxidizing nature, the high solubility of Methanesulfonic acid (MSA)s salts and the absence of color and odor.

Methanesulfonic acid (MSA)/SiO2 (1 mL/0.3 g) was found to be as an expeditious mixture in the synthesis of 2-substituted aromatic and aliphatic benzothiazoles at 140 °C using carboxylic acids.
After a simple workup, benzothiazoles were obtained in good yields.
Simplicity, use of widely available and diverse carboxylic acids, and easy handling of the reaction conditions are among the benefits of the method.

Concentrations of aerosol Methanesulfonic acid (MSA) and non-sea-salt (nss) sulfate were measured at six island stations in the Pacific Ocean to investigate regional and seasonal patterns of organosulfur emissions and the origin of nss sulfate over the Pacific.
The mean Methanesulfonic acid (MSA) concentrations, in μg/m3, at the stations were: Shemya, 0.097±0.098; Midway, 0.029±0.021; Fanning, 0.044±0.012; American Samoa, 0.026±0.012; New Caledonia, 0.021±0.009; Norfolk, 0.024±0.019.

The extremely high Methanesulfonic acid (MSA) levels found at Shemya indicate a major source of organosulfur emissions in the western North Pacific.
Significant seasonal trends in Methanesulfonic acid (MSA) were observed, with higher Methanesulfonic acid (MSA) occurring during warm months.
The amplitude of the seasonal variation was greatest at higher latitude stations.

At Fanning and American Samoa, which have minimal input of continental material, there is a significant positive correlation between Methanesulfonic acid (MSA) and nss sulfate.
Methanesulfonic acid (MSA)/nss sulfate ratios at other Pacific stations exhibit greater variability, which may be related to variations in: the input of continentally derived sulfate, the composition of oceanic organosulfur emissions, and atmospheric reaction pathways.

Methanesulfonic acid (MSA) (Methanesulfonic acid (MSA), 70 wt %) is widely used in electrochemical systems and is an excellent catalyst for the esterification, alkylation, and condensation of organic compounds.
Lower reaction temperatures are required when using Methanesulfonic acid (MSA) rather than titanate catalysts, and purer, more colorless products can be obtained using Methanesulfonic acid (MSA) than those produced using sulfuric or para-toluenesulfonic acid as the catalyst.

Anhydrous Methanesulfonic acid (MSA) is also particularly well suited for pharmaceutical applications and as a catalyst for aromatic alkylation.
The current commercial process for the synthesis of Methanesulfonic acid (MSA) involves chlorine oxidation of methylmercaptan.
While this process is highly productive, Methanesulfonic acid (MSA) produces six moles of HCl per mole of Methanesulfonic acid (MSA), resulting in a coupling of the demand for the primary product and the byproduct.

As an alternative Methanesulfonic acid (MSA) is interesting to consider a direct methane sulfonation route using SO3 or SO2 and O2 as the sulfonating agent.
Sen and co-workers and, more recently, we have shown that a compound such as K2S2O8 can be used as a free radical initiator to sulfonate methane with SO3 in fuming sulfuric acid.

Methane sulphonic acid is an alkanesulphonic acid and its chemical formula is CH3SO3H.
Methanesulfonic acid (MSA) is a strong acid having pKa= 1.9 and completely ionized in 0.1 M in an aqueous solution and has small affinity to oxidize organic compounds, less corrosive and toxic than other mineral acids.
Methanesulfonic acid (MSA) is also biodegradable and not evolve toxic gases.

Therefore Methanesulfonic acid (MSA) is considered as green acid.
Therefore Methanesulfonic acid (MSA)s use in organic synthesis attracts many chemists to use in organic synthesis.
In this review we described the Methanesulfonic acid (MSA) catalyzed organic transformation.

Since Methanesulfonic acid (MSA), does not cause sulfonation of aromatic rings, Methanesulfonic acid (MSA) was used at elevated temperatures to prepare 1-indanones and 1-tetralones through cyclization of 3-arylpropanoic and 4-arylbutanoic acids.
The twelve ketones which were prepared from Methanesulfonic acid (MSA)-catalyzed cyclization of 3 and 4-aryl substituted carboxylic acids are pesented in a table, along with their yields, time and temperature.

Studies under a variety of temperatures, concentrations and reaction times show that 30 min. to 3 hours is needed for cyclization depending on the reactivity of the starting material.
The use of neat Methanesulfonic acid (MSA) as a substitute for Friedel-Crafts catalyst was not promising.
Trial studies in which m-xylene was treated with acetic acid in the presence of anhydrous Methanesulfonic acid (MSA) at 110/sup 0/C for 3 hours gave low yields of acetylation product (ca. 30%), and gas chromatography analysis of the product showed unreacted m-xylene.