WO2020126855A1

WO2020126855A1 - Mixture comprising methanesulfonic acid and sulfuric acid

Info

Publication number: WO2020126855A1
Application number: PCT/EP2019/084972
Authority: WO
Inventors: Timo Ott; Ingo Biertuempel; Jens RIEGGER
Original assignee: Basf Se
Priority date: 2018-12-21
Filing date: 2019-12-12
Publication date: 2020-06-25

Abstract

The present invention relates to the use of a mixture of methanesulfonic acid and sulfuric acid as an acid and a substitute for methanesulfonic acid and/or mineral acids, especially hydrochloric acid, nitric acid, sulfuric acid and/or phosphoric acid, in industrial products and processes. The inventive mixture is obtainable by the direct reaction of methane and sulfur trioxide in sulfuric acid as solvent.

Description

Mixture comprisinq methanesulfonic acid and sulfuric acid

The present invention relates to the use of a mixture of methanesulfonic acid and sulfuric acid as an acid and a substitute for methanesulfonic acid and/or mineral acids, especially hydrochlo ric acid, sulfuric acid, nitric acid and/or phosphoric acid, in industrial products and processes. The inventive mixture is obtainable by the direct reaction of methane and sulfur trioxide in sulfu ric acid as solvent.

Mineral acids, such as sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid, are among the most important and simplest acids and are widely used in a vast variety of industrial products and processes. They are cheaply available in large amounts and characterized by their strong acidity, but also their strong corrosivity, their oxidative properties and their tendency to produce harmful vapours.

In the context of efforts to minimize the use and generation of hazardous materials, there is in creasing interest in the identification and employment of acids, which are environmentally friendly and biologically degradable. Alkanesulfonic acids are organic acids that can reach a simi lar acid strength as that of inorganic mineral acids, for example, sulfuric acid. However, in contrast to usual mineral acids such as sulfuric and nitric acids, the sulfonic acids are non-oxidizing and do not give off vapors that are harmful to health, as can be observed with hydrochloric and nitric acids. Furthermore, many sulfonic acids and particularly methanesulfonic acid, are biologically degrada ble. The applications of sulfonic acids are many, for example, in cleaning agents, surfactants, gal vanic and electronic industry, as catalysts, and in organic synthesis, pharmaceutical chemistry, for example, as protective groups. The salts of sulfonic acids are employed, for example, as surfac tants, for example, sodium dodecylsulfonate, or in the electroplating industry, especially as tin, zinc, silver, lead and indium, but also other metal, alkylsulfonates. Furthermore, organic salts are em ployed in pharmaceutical chemistry. The very high solubility of alkyl sulfonates plays an important role, in particular. Further, no harmful gases are formed in electrolysis, and the use of toxic com pounds, for example cyanide, which is common in many cases, is dispensed with.

The structurally simplest representative of alkanesulfonic acids is methanesulfonic acid. US 2,493,038 describes the preparation of methanesulfonic acid from SO₃ and methane. US 2005/0070614 describes further methods for preparing methanesulfonic acid, and its application.

WO 2007/136425 A2 discloses the use of the compound di(methanesulfonyl) peroxide (DMSP), which must be prepared by a complex electrolysis and, in addition, is a crystallizable highly explo- sive solid, as an initiator in a reaction in which methanesulfonic acid is formed from sulfur trioxide and methane.

WO 2015/071365 A1 and WO 2015/071455 A1 both describe processes for the sulfonation of alkanes. The main steps are:

1)Synthesis of an initiator/initiator-solution.

2) Preparation of a sulfur trioxide-solution (oleum) by dissolving sulfur trioxide in an inert sol vent (e.g. sulfuric acid)

3) Reaction of oleum with the corresponding alkane after or during addition of the initiator/ in itiator- solution in a high-pressure-reactor.

4)Quenching of non-reacted starting material

5) Purification (e.g. distillation, crystallization etc.)

6) Recycling of the inert solvent (e.g. sulfuric acid).

Particularly if sulfuric acid is employed as solvent, a mixture of an alkanesulfonic acid and sulfu ric acid may obtained with a high degree of purity.

Although, strong acids such as mineral acids and alkanesulfonic acids, particularly methanesul fonic acids, are essential for many applications in industrial products and processing, as de scribed above, they also show some disadvantages. Some mineral acids are strongly oxidizing and corrosive or may produce harmful vapors. Particularly methanesulfonic acid also shows a strong corrosivity and may for example corrode stainless steel vessels, when employed in in dustrial processes. Furthermore, methanesulfonic acid is expensive and therefore not abun dantly available.

It is thus the object of the present invention to overcome said disadvantages of the aforemen tioned acids and their use in prior art industrial products and processes. Particularly, disad vantages relating to strong corrosivity, oxidizing properties and harmful side-products should be avoided.

In a first embodiment, the object of the invention is solved by the use of a mixture comprising methanesulfonic acid and sulfuric acid as acid in industrial products and processes. Preferably, said mixture comprising methanesulfonic acid and sulfuric acid is used as a substitute for me thanesulfonic acid and/or mineral acids, especially hydrochloric acid, nitric acid, sulfuric acid and/or phosphoric acid, in industrial products or processes. Surprisingly it was found that when a mixture of methanesulfonic acid and sulfuric acid is em ployed as generic acid substance in industrial products and processes, some of the disad vantages involved with the use of methanesulfonic acid or minerals acids as standalone acids can be avoided. Particularly it was found that a mixture of methanesulfonic acid and sulfuric, albeit having a higher acid strength, shows a lower corrosivity than the respective isolated ac ids. Especially, it was surprisingly discovered that while methanesulfonic acid may corrode stainless steel materials, the inventive mixture does not corrode stainless steel materials. When the inventive mixture is used as a substitute for methanesulfonic acid, the necessary amount of expensive methanesulfonic is lowered which makes the process more econonomic.

Without the intention of being bound by theory, it is believed that the aforementioned surprising properties of the inventive mixture are a result of the reducing properties of methanesulfonic acid and the oxidizing properties of sulfuric acid. The carbon-sulfur bond in methanesulfonic acid is believed to act as a reducing agent, that may attack an oxide layer on the surface of stainless steel materials. Sulfuric acid on the other hand is known to be an oxidizing agent. It is believed that the two effects compensate each other and result in a lower corrosivity of the in ventive mixture in comparison with the respective acids, while the acid strength remains similar.

In contrast to hydrochloric acid and nitric acid, methanesulfonic acid and sulfuric acid do not produce harmful vapors and are considered to be environmentally sustainable.

Since a mixture of methanesulfonic acid and sulfuric acid has a higher acid strength than the isolated acids, it is more effective in solving impurities or dirt, when employed in cleaning pro cesses. In galvanic processes, a mixture of methanesulfonic acid and sulfuric acids is less in clined to generate metallic oxides, which form insoluble substances such as SnC>₂, than the iso lated acids.

Furthermore, a mixture of methanesulfonic acid and sulfuric will have a different density than the isolated acids depending on concentration, while retaining the properties of the acids, such that the density might be adjusted, if desirable. In contrast to isolated methanesulfonic acid, a mixture with sulfuric acid does not have a melting point near room temperature and thus can be handled more easily as a fluid.

According to the invention, the mixture comprising methanesulfonic acid and sulfuric acid may be used in any industrial product of process, where a strong acidic substance is required. In the following, particularly preferred uses are described. The description is meant to be exemplary and not to limit the invention, which also pertains to other industrial products and processes. Preferably, the mixture comprising methanesulfonic acid and sulfuric acid may be used as acid in industrial products and processes relating to cleaning and caring. Particular examples of such uses concern cleaners, dishwashing, sanitary cleaners, softening agents, descaling and rust removal.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to home care. Particular examples of such uses concern hard surface cleaning, dishwashing, softening agents and drain cleaners.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to industrial and institutional cleaning. Par ticular examples of such uses concern commercial laundry, food and beverage processing, par ticularly including milk, cheese, beer and wine processing, food service and kitchen hygiene, industrial cleaning, institutional cleaning and sanitation, vehicle and transportation care, scale removal ethanol production (clean in place, CIP), metal cleaning, concrete cleaning and/or membrane cleaning.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to water treatment. Particular examples of such uses concern cleaning agents and/or descaling agents.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to regeneration ion exchange resins.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to galvanic applications. Particular examples of such uses concern electronics, electroplating industries, electroplating baths, tine plates (ETL, electrolytic tinning line) and/or electroplating of plastics. Particular examples of products and processes concerning electronics are printed circuit boards, stripping and etching process es and/or electropolishing.

In relation to galvanic applications, the mixture comprising methanesulfonic acid and sulfuric acid has the particular advantage of a low risk of corrosion and of being particularly cost- efficient.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to the oil and gas industry and/or the mining industry. Particular examples of such uses concern primary metal industries, mining, especially descaling solutions for the mining industry, oilfield solutions, especially stimulation chemicals and/or acids, particularly unconventional oil and gas production such as oil sands.

In the field of mining, a mixture comprising methanesulfonic acid and sulfuric acid may particu larly be used as a substitute for hydrochloric acid or pure methanesulfonic acid. Furthermore, the mixture may be used for leaching processes, such as heap leaching, particularly in the pro duction, purification and/or extraction of copper, uranium, nickel, gold and/or zinc. Especially the mixture may be used as a substitute for cyanide-based agents and in relation to molten metal sulfide phases (matte).

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to metal processing. Particular examples of such uses concern steel mills, coil and wires, aluminum processing and coloring.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to pharmaceutical, chemical and agrochemi cal industries. Particular examples of such uses concern feedstocks for synthesis, uses as cata lyst, uses as Bronstedt acids, salification/mesylation, especially pharma and/or dyestuff, uses as solvents, esters, paints, coating and adhesives, oleochemicals, pvc plastiziers (esterifica tion), uses for introducing mesylate as a protecting group in organic synthesis and uses for the synthesis of mesylates, for example in pharmaceuticals.

Furthermore, the mixture may be used as solvent for the sulfonation of methane, particularly the reaction of methane with sulfur trioxide to methanesulfonic acid.

The mixture comprising methanesulfonic acid and sulfuric acid may for example be used as a Bronstedt acid in alkylation reactions, esterification reactions, acylation reactions, cyclization reactions, rearrangement reactions, neutralization reactionsand/or polymerization reactions.

The mixture comprising methanesulfonic acid and sulfuric acid may for example be used as a solvent in polymer production and/or oxidation reactions.

Particularly, the mixture comprising methanesulfonic acid and sulfuric acid may be used as catalyst in the production of biopolymers, the pre-treatment of lignocellulose and/or in the pro duction of levulinic acid. Generally, the mixture comprising methanesulfonic acid and sulfuric acid may be used in indus trial products and processes relating to organic liquids based on natural resources, particularly their purification and/or pre-treatment for subsequent conversion.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to biodiesel. Particular examples of such us es concern the production of biodiesel, uses as additive to biodiesel, uses in the filtration of nat ural organic fluids, purification of biodiesel and esterification.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to batteries. Particular examples of such uses concern redox-flow batteries and/or cerium batteries.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to recycling. Particular examples of such us es concern metal recycling and/or battery recycling, especially lead battery recycling.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used in industrial products and processes relating to borane generation.

In an alternative embodiment, the mixture comprising methanesulfonic acid and sulfuric acid is used as a feedstock to prepare methanesulfonylperoxides, for example dimethylsulfonylperox- ide (DMSP) and monomethylsulfonylperoxide (MMSP), by electrolysis or by reaction of methane with hydrogen peroxide and/or a metal peroxide.

Furthermore, the mixture comprising methanesulfonic acid and sulfuric acid may be used in the tanning of leather.

The weight ratio between methanesulfonic acid and sulfuric acid in the mixture, which is used according to the invention, is preferably in a range of from 0.1 :9 to 9:0.1.

More preferably, the weight ratio is in a range of from 3:7 to 7:3, most preferably in a range of from 2:3 to 3:2, especially 1 :1.

The mixture may comprise a solvent, especially water. Methanesulfonic acid and sulfuric acid preferably account for 50 to 100 % by weight of the mixture, more preferably 70 to 100 % by weight, particularly 80 to 100 % by weight, especially 90 to 100 % by weight. The mixture may consist of methanesulfonic acid and sulfuric acid. Particularly, the mixture may be essentially water-free in an alternative embodiment or may comprise very low amounts of water in comparison to mineral acids used in the prior art as ac ids in industrial products and processes. The mixture may therefore be used under circum stances, where water is detrimental to the product or processes.

The pH-value of the mixture, which is used according to the invention, is preferably below 0 or in a range of from -10 to 1 , more preferably in a range of from -10 to 0, most preferably in a range of from -10 to -2.

In a preferred embodiment, the mixture comprising methanesulfonic acid and sulfuric acid, which is used according to the invention, is obtainable by a reaction of sulfur trioxide and me thane, when the reaction is performed in a solvent comprising or consisting of sulfuric acid. Said reaction of sulfur trioxide and methane is preferably catalysed by an organic or inorganic perox ide stable at room temperature.

Suitable inorganic peroxides comprise peroxoacids of boron, silicon, phosphorus and sulfur. Said peroxoacids may be obtainable by a reaction of an oxoacid with a peroxide, especially hy drogen peroxide. The peroxoacid may comprise, especially consist of, a polyprotic acid com prising one or more peroxy groups -O-O-X, wherein X is H, Li, Na and/or K. The polyprotic acid may further comprise one or more groups -O-X, wherein X is H, Li, Na and/or K. The peroxoacid may for example comprise the reaction product of phosphoric acid with hydrogen peroxide or the reaction product of boric acid with hydrogen peroxide and/or potassium perox- omonosulfate.

Suitable organic peroxides comprise organic peroxoacids of sulfur, phosphorus, silicon, boron, nitrogen or carbon. The peroxoacid group of the organic peroxoacid preferably corresponds to R-E(=X)_m(-YZ)_n-0-0-Z, wherein E is selected from the group consisting of S, P, Si, B, N and C, wherein X and Y may be the same or different and are selected from the group consisting of O and S, wherein m is an integer of from 0 to 2, wherein n is an integer of from 0 to 2, and wherein Z is H, Li, Na and/or K. The peroxoacid group is preferably selected from the group consisting of R-SCL-O-O-X, R-CO-O-O-X,

R-P0(0H)-0-0-X, R-PS(0H)-0-0-X, wherein X is H, Li, Na and/or K.

R may be any organic radical. For example, R may be a branched or unbranched alkyl radical or a substituted alkyl radical comprising at least one functional group, preferably selected from the group consisting of carbon double bonds, carbon triple bonds, aryl groups, heteroaryl o

groups and functional groups comprising heteroatoms, especially functional groups comprising O, S, N, P, Si, B, Se, Te, F, Cl, Br, I, Mg or Li atoms.

Particular examples of peroxide catalysts comprise peroxoacids derived from alkanesulfonic acids, especially the peroxo derivative of methanesulfonic acid.

In an alternative embodiment, the problem of the invention is solved by a process comprising the steps of

i) providing a mixture comprising methanesulfonic acid and sulfuric acid by a reaction of sulfur trioxide and methane in a solvent comprising sulfuric acid, wherein an inorganic or organic peroxide stable at room temperature is employed as catalyst and

ii) utilizing said mixture in an industrial product or process as acid.

Examples for inorganic and organic peroxide, which may be employed in step i), are described above. Examples for industrial products and processes, for which the mixture may be utilized in step ii) are described above.

Preferably, the mixture is utilized in step ii) as substitute for methanesulfonic acid and/or mineral acids, especially hydrochloric acid, nitric acid, sulfuric acid and/or phosphoric acid, in industrial products or processes.

Particularly, the mixture may be used as acid in cleaning and caring, home care, industrial and institutional cleaning, water treatment, regeneration ion exchange resins, galvanic applications, oil and gas industry, mining, metal processing, pharmaceutical, chemical and agrochemical in dustry, biodiesel, batteries, recycling, borane generation or in the tanning of leather.

In a preferred embodiment of the inventive process, the mixture, which is produced in step i) of the process, is utilized in step ii) of the process without any intermediate step of isolating or puri fying the mixture. In a preferred embodiment of the inventive process, steps i) and ii) are per formed on the same site and/or the mixture produced in step i) is immediately transferred to the use in step ii).

Claims

1. Use of a mixture comprising methanesulfonic acid and sulfuric acid as acid in industrial products and processes.

2. Use according to claim 1 , wherein the mixture is used as substitute for methanesulfonic acid and/or mineral acids, especially hydrochloric acid, nitric acid, sulfuric acid and/or phosphoric acid, in industrial products or processes.

3. Use according to claim 1 or 2, wherein the mixture is used as acid in cleaning and caring, home care, industrial and institutional cleaning, water treatment, regeneration ion ex change resins, galvanic applications, oil and gas industry, mining, metal processing, pharmaceutical, chemical and agrochemical industry, biodiesel, batteries, recycling, bo- rane generation or in the tanning of leather.

4. Use according to one or more of claims 1 to 3, wherein the weight ratio between sulfuric acid and methanesulfonic acid within the mixture is in a range of from 0.1 :9 to 9:0.1.

5. Use according to claim 4, wherein the weight ratio between sulfuric acid and methanesul fonic acid within the mixture is in a range of from 4:6 to 6:4.

6. Use according to one or more of claims 1 to 5, wherein the mixture comprises a solvent, especially water.

7. Use according to one or more of claims 1 to 6, wherein the pH-value of the mixture is in a range of from -10 to 1 , especially -10 to 0.

8. Use according to one or more of claims 1 to 7, wherein the mixture is obtainable by a re action of sulfur trioxide and methane, when the reaction is performed in a solvent compris ing or consisting of sulfuric acid.

9. Use according to claim 8, wherein the reaction of sulfur trioxide and methane is catalysed by an organic or inorganic peroxide stable at room temperature.

10. Process comprising the steps of

i) providing a mixture comprising methanesulfonic acid and sulfuric acid by a reaction of sulfur trioxide and methane in a solvent comprising sulfuric acid, wherein an inor ganic or organic peroxide stable at room temperature is employed as catalyst, and ii) utilizing said mixture in an industrial product or process as acid.

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