7664-93-9
Chemical Name: Ultra-pure sulfuric acid/electronic grade sulfuric acid/refined sulfuric acid
Molecular weight: 98.08 g/mol
Concentration: Industrial grade sulfuric acid: 92%-98%. Reagent Grade: >98% or Ultra-Pure Sulfuric Acid Electronic Grade Sulfuric Acid >99.9999%
| parameter | um | minimum | utmost | |
| Assay (H2SO4) | % | 96.0 | 97.0 | |
| color | APHA | 5 | ||
| Chloride (Cl) | ppb | 50 | ||
| Nitrate (NO3) | per minute | 0.1 | ||
| Phosphate (PO4) | per minute | 0.1 | ||
| NH4 | per minute | 1 | ||
| Post-Igination Residue (RAI) | per minute | 1 | ||
| Reducing substance, permanganate (KMnO4) | per minute | 1 | ||
| The impurities are the largest | um | minimum | utmost | |
| Aluminum (Al) | ppb | 0.05 | ||
| Antimony (Sb) | ppb | 0.05 | ||
| Arsenic (As) | ppb | 0.05 | ||
| Barium (Ba) | ppb | 0.05 | ||
| Beryllium (Be) | ppb | 0.05 | ||
| Bismuth (Bismuth) | ppb | 0.05 | ||
| Boron (B) | ppb | 0.05 | ||
| Cadmium (Cd) | ppb | 0.05 | ||
| Calcium (Ca) | ppb | 0.05 | ||
| Chromium (Cr) | ppb | 0.05 | ||
| Cobalt (Co) | ppb | 0.05 | ||
| Copper (Cu) | ppb | 0.05 | ||
| Gallium (Ga) | ppb | 0.05 | ||
| Germanium (Ge) | ppb | 0.05 | ||
| Gold (AU) | ppb | 0.05 | ||
| Indium (In) | ppb | 0.05 | ||
| Iron (Iron) | ppb | 0.05 | ||
| Lead (Pb) | ppb | 0.05 | ||
| Lithium (Li) | ppb | 0.05 | ||
| Magnesium (Mg) | ppb | 0.05 | ||
| Manganese (Mn) | ppb | 0.05 | ||
| Molybdenum (Mo) | ppb | 0.05 | ||
| Mercury (Hg) | ppb | 0.05 | ||
| Nickel (Ni) | ppb | 0.05 | ||
| Niobium (Nb) | ppb | 0.05 | ||
| Potassium (K) | ppb | 0.05 | ||
| Selenium (Se) | ppb | 0.05 | ||
| Silicon (Si) | ppb | 0.5 | ||
| Silver (Ag) | ppb | 0.05 | ||
| Sodium (Na) | ppb | 0.05 | ||
| Strontium (Sr) | ppb | 0.05 | ||
| Tantalum (Ta) | ppb | 0.05 | ||
| Thallium (Tl) | ppb | 0.05 | ||
| Tin (Sn) | ppb | 0.05 | ||
| Titanium (Ti) | ppb | 0.05 | ||
| Vanadium (V) | ppb | 0.05 | ||
| Zinc (Zn) | ppb | 0.05 | ||
| Zirconium (Zr) | ppb | 0.05 | ||
| Particle count | um | minimum | utmost | |
Physical and chemical properties
- Density: ~1.84 g/cm³ (at 20°C)
- Boiling point: ~290°C (decomposition before boiling)
- Melting point: ~10°C
- pH: Strongly acidic (pH <1)
- Solubility: Completely miscible with water (exothermic reaction)
- Decomposition: Produces SO₃, SO₂, and H₂O at high temperatures
- High purity: Extremely low impurity content to meet the stringent requirements of microelectronics industries such as semiconductors and VLSI.
- Colorless transparent oily liquid: Pure sulfuric acid is a colorless transparent oily liquid.
- Strong water absorption and oxidation: It has strong water absorption and can dehydrate and carbonize carbohydrates such as cotton, paper, and wood; At the same time, it has oxidizing properties and can react with most metals.
Main applications:
- Semiconductor industry:
- Critical for wafer cleaning and etching (SC-1 and SC-2 RCA cleaning)
- Removes organic contaminants and metal residues from microchips
- Electronics Manufacturing:
- High-purity etching solutions for PCBs and microfabrication
- A critical component in the Chemical-Mechanical Planarization (CMP) process
- Pharmaceutical and chemical synthesis:
- High-purity reagents for precision chemical reactions
- Catalyst in high-purity sulfuric acid-mediated synthesis
- Batteries and Energy Storage:
- Lithium-ion and lead-acid battery production is essential
- Environmental and analytical applications:
- For ICP-MS and trace metal analysis
- Key reagents for ultrapure water production
Method of preparation
Vacuum distillation
Distilled sulfuric acid is collected by vacuum distillation using vacuum distillation.
Falling film crystallization
1. Crystallization process: adjust the temperature of the coolant in the constant temperature tank to the required temperature to cool down the crystallizer to a constant; Add a small amount of crystal seed hanging film to the crystallizer, transport the feed acid and distilled acid according to a certain material liquid flow, and cool it down at a certain cooling rate, cool to the end of crystallization, and stop the feed acid transportation.
2. Sweating process: The thermostatic groove is heated in a certain step to increase the temperature of the crystallizer, so that the crystal part melts and discharges in the form of sweat, and the temperature rises until the end of sweating stops.
3. Melting process: increase the temperature of the crystallizer to melt all the crystals, that is, the product.
Safety and handling
- Hazards: Strong acid, highly corrosive, causing severe burns, violent reactions with water and organic substances.
- Storage:
- Use acid-resistant containers (PTFE, PFA, or specialized HDPE)
- Store in a cool, dry, well-ventilated place away from heat sources
- Protective Gear: Use chemically resistant gloves, face shields, acid-resistant clothing, and work under fume hoods.
Ultrapure acid refers to acid chemicals with high purification and very low impurity content, which are widely used in high-end industrial fields such as semiconductors, microelectronics, and optoelectronics. Common ultra-pure acids include ultra-pure sulfuric acid, ultra-pure nitric acid and ultra-pure hydrofluoric acid.
- Ultra-pure sulfuric acid: also known as electronic-grade sulfuric acid, with extremely high purity and low impurity content, it is an indispensable key basic chemical reagent in the development of microelectronic technology, and is widely used in large-scale integrated circuits, semiconductors and other microelectronics industries.
- Ultra-pure nitric acid: With high purity and low impurity content, it is used in semiconductor manufacturing, surface treatment and cleaning of high-precision electronic components.
- Ultrapure hydrofluoric acid: Used in glass etching, cleaning and etching processes in semiconductor manufacturing.
