MEK

What is MEK (Methyl Ethyl Ketone)?

MEK, full name Methyl Ethyl Ketone, chemically designated as 2‑Butanone, is a core fast‑drying low‑carbon aliphatic ketone organic solvent in the petrochemical industry and a highly versatile basic chemical raw material for global industrial fields.

High‑purity MEK is a colorless, transparent and highly fluid liquid with a slight acetone‑like characteristic odor. It features strong dissolving power, moderate volatilization rate, excellent film‑forming performance and wide solvent compatibility. Fully miscible with water, alcohols, ethers, esters, aromatics, alkanes and most organic solvents, MEK can form azeotropic mixtures with water, making it suitable for multi‑system chemical formula processes.

MEK maintains stable chemical properties at normal temperature and pressure, resisting decomposition and spontaneous polymerization. It possesses typical ketone chemical reactivity and can undergo addition, condensation, oxidation and other organic reactions. It is widely applied in coatings, inks, adhesives, synthetic leather, electronic precision cleaning, fine chemical synthesis, pharmaceutical and pesticide intermediate preparation and other fields.

Core Physicochemical Basic Parameters of MEK (Methyl Ethyl Ketone)

Mainstream Industrial Production Processes of MEK

1. N‑Butene Process (Mainstream Core Industrial Process)

Adopting n‑butene (1‑butene, cis/trans‑2‑butene) from refinery by‑product C4 fraction as the core raw material, the process consists of two key procedures: n‑butene hydration to sec‑butanol and sec‑butanol dehydrogenation to MEK, featuring high process controllability and stable product quality.

Step 1: Preparation of Sec‑Butanol via N‑Butene Hydration

Three industrial technical routes are available based on different catalysts and working conditions, among which the resin‑catalyzed direct hydration process is currently the optimal solution in terms of technology and economy.

(1) Indirect Sulfuric Acid Hydration Process (Traditional Process)

Process Principle: N‑butene reacts with 80% sulfuric acid to form sulfate ester intermediates, which are diluted and hydrolyzed to obtain aqueous sec‑butanol solution, with sulfuric acid recyclable.

Reaction Equations

(2) Resin‑Catalyzed Direct Hydration Process (Optimal Mainstream Process)

Process Principle: Using strong acidic sulfonic acid cation exchange resin as catalyst, n‑butene reacts directly with water under high temperature and pressure (150~170 ℃, 5.0~7.0 MPa) to synthesize sec‑butanol, featuring no acid‑base waste liquid pollution and lower energy consumption.

Reaction Equation

(3) Heteropoly Acid‑Catalyzed Direct Hydration Process

Process Principle: Adopting heteropoly acids such as phosphomolybdic acid as catalysts, direct hydration of n‑butene is realized under high pressure (200~230 ℃, approx. 19 MPa), suitable for high‑purity raw material systems.

Step 2: Preparation of MEK via Sec‑Butanol Dehydrogenation

Purified sec‑butanol undergoes gas/liquid catalytic dehydrogenation reaction to remove hydrogen and generate high‑purity MEK, with high reaction conversion rate and few by‑products.

Reaction Equation

2. Sec‑Butyl Acetate Hydrogenation Process (Emerging Optimized Chinese Process)

As a green process promoted by Chinese refining and chemical enterprises in recent years, it features mild reaction conditions, high conversion efficiency and low three‑waste emissions, and can co‑produce ethanol to greatly improve raw material added value.

Process Principle: Taking post‑ether C4 and acetic acid as initial raw materials, sec‑butyl acetate is first synthesized, then reduced by hydrogenation to generate sec‑butanol, and finally dehydrogenated to produce finished MEK.

Stepwise Reaction Equations

3. Niche Auxiliary Production Processes

(1) N‑Butane Liquid‑Phase Oxidation Process: Using n‑butane as raw material, liquid‑phase oxidation is carried out under the conditions of cobalt acetate‑sodium acetate catalyst, 150~225 ℃ and 4.0~8.0 MPa. The main product is acetic acid, with MEK as a by‑product (accounting for about 16% of acetic acid output), only applicable to large‑scale acetic acid co‑production units.

(2) Isobutylbenzene Process: N‑butene and benzene undergo alkylation catalyzed by aluminum trichloride to generate isobutylbenzene, followed by liquid‑phase oxidation and acidolysis reactions to simultaneously produce MEK and phenol, mostly used in fine chemical co‑production scenarios.

MEK Product Grades, Indicators and Applicable Scenarios

MEK is divided into industrial grade and reagent grade according to purity and impurity control standards. Different grades with precise indicator differences are adapted to differentiated scenarios including general industry, precision synthesis, laboratory scientific research and electronic high‑precision cleaning, and cannot be replaced arbitrarily.

1. Industrial‑Grade MEK (Mass‑Produced General Model)

Industrial Grade Type Ⅰ (Purity ≥99.8%): Strict impurity control, water content ≤0.05%, acidity ≤0.003%, evaporation residue ≤0.001%, acetone ≤0.1%. Suitable for mid‑to‑high‑end industrial scenarios such as coating dilution, printing ink solvent, resin dissolution and pharmaceutical intermediate synthesis.

Industrial Grade Type Ⅱ (Purity ≥99.5%): Water content ≤0.1%, acidity ≤0.005%, evaporation residue ≤0.002%, acetone ≤0.3%. Applied to general scenarios including conventional electronic component cleaning, glue dilution, leather degreasing and rubber solvents.

Industrial Dilution Grade (Purity 80%‑90%): Water content ≤0.3%, acidity ≤0.01%, evaporation residue ≤0.005%, acetone ≤0.5%. Only used for ordinary industrial cleaning, substrate degreasing and auxiliary dilution of low‑requirement coatings.

2. Reagent‑Grade MEK (Laboratory/Scientific Research Special Use)

Guaranteed Reagent (GR, Purity ≥99.9%): Total impurities ≤0.003%, water content ≤0.02%, heavy metals ≤0.00005%, acetone ≤0.03%. Suitable for high‑precision trace detection, gas chromatographic analysis and high‑end scientific research experiments.

Analytical Reagent (AR, Purity ≥99.8%): Total impurities ≤0.005%, water content ≤0.03%, heavy metals ≤0.0001%, acetone ≤0.05%. Widely used for routine laboratory analysis, sample extraction, organic synthesis and chromatographic solvents.

Chemical Pure (CP, Purity ≥99.5%): Total impurities ≤0.01%, water content ≤0.08%, heavy metals ≤0.0002%, acetone ≤0.2%. Applicable to teaching experiments, routine industrial quality inspection and basic solvent use.

Analysis of MEK Industrial Chain

MEK is a core high‑end solvent for deep processing of the petrochemical C4 industrial chain. China has a sound industrial chain layout, concentrated units and prominent large‑scale production capacity advantages. The upstream and downstream supporting facilities are mature, enabling full‑process independent production and stable supply, making China a global core MEK production and export base.

Core Upstream Raw Materials

Refined C4 fraction, n‑butene, sec‑butanol, acetic acid, high‑purity hydrogen, copper‑zinc dehydrogenation catalyst, palladium‑based oxidation catalyst, industrial purified water

Core Downstream Application Fields

Industrial Solvents: Coating and paint dilution, printing ink solvents, adhesive solvents, PU synthetic leather slurry solvents, industrial degreasing and cleaning

Precision Manufacturing: Precision cleaning of electronic components and semiconductor panels

Fine Chemicals: Synthesis of pharmaceutical and pesticide intermediates, solvents for various organic chemical reactions

MEK Storage, Transportation and EHS Operational Safety Specifications

1. Storage Specifications

Store exclusively in explosion‑proof and anti‑static hazardous chemical warehouses for flammable liquids; strictly control warehouse temperature ≤37 ℃, and keep away from open flames, high‑temperature heat sources, static electricity generating devices and strong oxidants at all times.

Keep material containers fully sealed at all times to avoid volatilization loss and water vapor infiltration and prevent material deterioration.

All electrical and lighting equipment in the warehouse shall be explosion‑proof and anti‑static; store materials in independent zones, and mixed storage with strong acids, strong alkalis and strong oxidants is strictly prohibited.

Establish complete precursor chemical inbound and outbound ledger and regular inventory system; maintain forced ventilation in the warehouse, equipped with absorbent cotton, inert sand, special fire‑fighting equipment and leakage emergency containment facilities.

2. Transportation Specifications

Strictly implement UN1193 Class 3 flammable liquid dangerous goods transportation standards; carriers, drivers and escorts must hold compliant qualifications for hazardous chemical and precursor chemical transportation.

Ensure full sealing, leakage prevention, sun protection, rain protection and moisture protection during transportation, and avoid high‑temperature exposure.

Mixed transportation with oxidants, strong acids and edible goods is strictly prohibited to eliminate combustion and explosion risks and cross contamination.

Keep complete transportation ledgers throughout the process to comply with the circulation supervision requirements of precursor chemicals.

3. On‑site Operation and Emergency Specifications

Completely eliminate all ignition sources such as open flames, static electricity and high temperature in the operation area, and maintain continuous forced ventilation to prevent vapor accumulation in confined spaces.

Operators must wear organic vapor gas masks, protective goggles and solvent‑resistant nitrile gloves for full personal protection.

Contact Emergency Treatment: In case of accidental skin or eye contact with materials, rinse continuously with a large amount of running water immediately and seek medical attention if discomfort occurs.

Leakage Emergency Treatment: Cut off all surrounding fire sources first, contain and trap leaked materials with inert sand and absorbent cotton. Direct water flushing is strictly prohibited to prevent material diffusion and secondary combustion and explosion risks.

Frequently Asked Professional Questions (FAQ)

Q: What are the core differences between industrial‑grade, high‑purity and electronic‑grade MEK, and how to select models?

A: The three grades have identical chemical molecular structures, with core differences lying in the precision control of moisture, trace organic impurities, metal ions and micro particles, and they are not interchangeable in application scenarios.

Industrial‑grade MEK: Cost‑effective with qualified basic impurities, suitable for general industrial scenarios such as coatings, inks, adhesives and synthetic leather.

High‑purity refined MEK: Strictly controlled moisture and trace impurities, narrow distillation range and stable quality, applicable to high‑end coatings, special resin synthesis and precision industrial cleaning.

Electronic‑grade MEK: Ultra‑deep refining with metal ions and micro impurities controlled at PPB level, specially used for high‑precision cleaning of semiconductors, panels and electronic components.

Selection Core Standard: Focus on moisture indicators. Excessive moisture will cause paint film whitening, adhesive layer defects and electronic component pollution, and downgraded substitution is prohibited in high‑precision manufacturing scenarios.

Q: What compliance qualifications do enterprises need for MEK procurement?

A: MEK is a national Category 3 precursor chemical under strict supervision with rigorous compliance requirements for procurement and use. Enterprises must complete filing for precursor chemical use/operation with public security departments in advance to obtain legal qualifications. Establish full‑process ledgers for inbound and outbound registration, storage management, usage records and waste disposal. Procurement is only allowed from qualified formal suppliers; unfiled procurement, private transfer, resale and illegal waste disposal are strictly forbidden.

Q: How to distinguish and select between MEK and acetone for industrial application?

A: The core differences lie in volatilization rate, dissolving power and film‑forming stability, and the selection is based on process quality requirements:

Acetone: Extremely fast volatilization and lower cost, but prone to cause paint film pinholes, whitening and orange peel defects, only suitable for low‑cost ultra‑fast drying simple working conditions.

MEK: Higher boiling point, uniform and gentle volatilization, far superior dissolving power to acetone, forming flat and defect‑free paint films and adhesive layers with excellent stability. It adapts to most industrial scenarios requiring high process quality and finished product stability.

China's MEK industry is supported by abundant C4 refining resources and mature core production processes, boasting world-leading production capacity. It can steadily supply full-grade products with quality comparable to imported international materials, meeting the essential demands of high-end manufacturing and fine chemicals across all sectors. Leveraging China's large MEK market advantages, 7DCHEM focuses on the chemical markets of Central and Eastern Europe and Ukraine. Supported by China's integrated chemical industrial chain resources, we have built a seven-dimensional value-added service system covering procurement, custom manufacturing, private branding, packaging processing, green compliance, authoritative testing and long-term ESG risk management. Focused on chemical supply chain planning, compliance risk control and local delivery, we provide professional chemical solutions for clients in Central and Eastern Europe and Ukraine.