Complete Detailed Product Specification – n-Butyl Isocyanate (CAS 111-36-4)
1. Basic Identification Information
CAS No.: 111-36-4
Chemical Name: n-Butyl isocyanate
IUPAC Name: Isocyanatobutane
Synonyms: Butyl isocyanate, 1-isocyanatobutane, n-BIC
EINECS No.: 203-867-6
MDL No.: MFCD00002047
Molecular Formula: C₅H₉NO
Structural Formula: CH₃CH₂CH₂CH₂-N=C=O
Molecular Weight: 99.13
SMILES: CCCCN=C=O
UN Number: UN 2485
HS Code: 29291090
Hazard Classification: Class 6.1 Toxic + Class 3 Flammable Liquid + Class 8 Corrosive Substance, Packing Group II
Chemical Category: Aliphatic monoisocyanate, high-activity acylation & urethane synthesis intermediate
2. Physical & Chemical Properties
Appearance
Colorless transparent mobile oily liquid with strong sharp irritating pungent odor; extremely fuming in humid air, instantly generates white mist from reaction with water vapor.
Core Physical Constant Table
| Parameter | Standard Value | Remarks |
| Melting Point | -76 ℃ | Low freezing point, no crystallization under normal storage |
| Boiling Point | 114–116 ℃ (760 mmHg) | Distillable under normal pressure |
| Density (20 ℃) | 0.880–0.884 g/mL | Lighter than water |
| Refractive Index n₂₀/D | 1.406–1.408 |
|
| Closed Cup Flash Point | 26 ℃ | Highly flammable, Class 3 flammable liquid |
| Autoignition Temperature | 420 ℃ |
|
| Explosion Limit in Air (V/V) | 1.2% ~ 9.5% | Wide explosive range |
| Vapor Pressure (20 ℃) | 18 mmHg | Highly volatile, toxic vapor easily spreads |
| Solubility in Water | Instant violent exothermic reaction, cannot dissolve | Reacts to produce n-butylamine + CO₂ |
| Organic Solvent Solubility | Fully miscible with anhydrous toluene, xylene, dichloromethane, ethyl acetate, acetone, anhydrous ether; strictly incompatible with alcohol, amine, water-containing solvents |
|
| pH after hydrolysis | Strongly alkaline |
|
Key Chemical Characteristics
- Ultra-active isocyanate group (-NCO), core characteristic reaction:
- Reaction with alcohol → Urethane (carbamate)
- Reaction with primary/secondary amine → Urea derivatives
- Reaction with water (even trace moisture) → Amine + carbon dioxide, severe foaming, heat release
- Reaction with carboxylic acid → Amide + CO₂
- Self-polymerization risk under heating or trace alkali catalyst, generates butyl isocyanate dimer/trimer, causing viscosity rise and solid precipitation.
- Strong irritant & corrosive: Vapor severely damages respiratory tract, eyes, mucous membranes; liquid causes blistering chemical burns on skin.
- Light & heat sensitive; long-term storage needs nitrogen sealing, low temperature to slow polymerization and discoloration.
- Incompatibility list: Water, alcohols, amines, strong acids, strong alkalis, reducing agents, metal oxides.
3. Export Industrial Quality Standard (Premium Grade ≥99.0%)
| Test Item | Standard Spec | Test Detection Method |
| n-Butyl isocyanate Purity | ≥99.0 % | GC Gas Chromatography |
| Free n-Butylamine Impurity | ≤0.10 % | GC / Acid-base titration |
| Hydrolysis Residue (Urea dimer) | ≤0.30 % | GC |
| Moisture Content | ≤50 ppm | Karl Fischer Titration (strictly anhydrous detection environment) |
| Color (APHA/Hazen) | ≤30 | Platinum-Cobalt Colorimetry |
| Distillation Range (113–117 ℃) | ≥95 vol% | Distillation Test |
| Appearance | Colorless clear fuming liquid without suspended solids or turbidity | Visual Inspection |
High-Purity Pharma Grade (≥99.5%)
Ultra-low amine and dimer impurities, moisture <20 ppm, nitrogen vacuum sealed packaging, exclusively for amino acid protection and heterocyclic API synthesis.
4. Main Industrial Application Fields
4.1 Pharmaceutical & Peptide Synthesis (High-value Core Application)
- Amino group blocking reagent: Reacts with amino acid side chains to form butyl urea protecting group for multi-step solid-phase peptide synthesis, easily deprotected under acidic hydrolysis.
- Heterocyclic drug intermediate: Build urea, imidazole, pyrimidine nitrogen-containing heterocyclic skeletons for antibacterial, anti-inflammatory and anti-tumor APIs.
- Raw material for synthetic carbamate drug intermediates, pesticide pharmaceutical chiral resolution auxiliary.
4.2 Agrochemical Intermediates
- Manufacture of urea herbicides, fungicides and insecticides; aliphatic butyl chain improves compound lipophilicity, enhances crop absorption efficiency.
- Synthesis of pesticide synergist and plant growth regulator carbamate derivatives.
4.3 Fine Chemical Urethane & Polymer Raw Material
- Monoisocyanate modifier for polyurethane resin, coating and adhesive; introduces flexible butyl segment to improve film flexibility and low-temperature resistance.
- Raw material for blocked isocyanate crosslinker, used in single-component baking coatings.
- Synthesis of organic synthesis catalysts, chelating agents via alcohol/amine addition reaction.
4.4 Laboratory Organic Synthesis Reagent
Universal N-acylation reagent for selective modification of hydroxyl and amino groups; widely used in total synthesis of complex natural products and biochemical labeling experiments.
4.5 Other Scenarios
- Surfactant intermediate for water treatment bactericides;
- Metal surface passivation auxiliary, anti-rust coating additive.
5. Safety, Packaging, Storage & Transportation Regulations
GHS Hazard Classification
- Flammable Liquid Category 3
- Acute Inhalation Toxicity Category 2
- Skin Corrosion Category 1B, Serious Eye Damage Category 1
- Specific Target Organ Toxicity Single Exposure Category 3 (respiratory tract)
Signal Word: Danger
Main Hazard Statements:
H226 Flammable liquid and vapor
H330 Fatal if inhaled
H314 Causes severe skin burns and eye damage
H335 May cause respiratory irritation
H290 May be corrosive to metals
H260 In contact with water releases flammable gases which may ignite spontaneously
Export Standard Packaging (Strictly Anhydrous Nitrogen Sealed)
- Industrial bulk grade: 200L lined anti-corrosion steel drum, vacuum nitrogen filling inner seal to isolate moisture and air
- Small trial order: 25L plastic-lined iron drum / 5L metal sealed can
- Pharma high-purity grade: Aluminum foil vacuum inner bag + light-proof iron drum, low-moisture barrier packaging
Mandatory Storage Requirements
- Independent Class A flammable toxic corrosive chemical warehouse, temperature controlled ≤25 ℃, full explosion-proof ventilation, negative pressure exhaust system.
- Strictly sealed with nitrogen protection; completely isolated from water, alcohols, amines, edible raw materials, oxidants and strong acids.
- Warehouse equipped with isocyanate gas leakage detector, full set of gas-proof respirators, acid/alkali resistant PPE, emergency eyewash station; water fire extinguishers are forbidden, only dry powder / CO₂ fire extinguishers allowed.
- Shelf life: 6 months under sealed low-temperature nitrogen storage; re-test purity and NCO content once expired, discard if polymerization turbidity appears.
Sea & Land Transportation Rules
UN 2485, Triple hazard: Class3 flammable liquid + Class6.1 toxic substance + Class8 corrosive goods, Packing Group II
- All packages must be fully waterproof and light-proof; prohibit loading/unloading in rainy humid environment to prevent drum leakage and moisture contact.
- Strictly no mixed loading with water-containing chemicals, alcohols, amines, oxidants, food additives in one container.
- Avoid direct sunlight and high-temperature stacking during transit; all vehicles must be explosion-proof with static grounding.
- Complete export clearance documents: COA, MSDS, TDS, IMDG marine dangerous goods declaration, hazard classification certificate.
6. E-commerce Listing Copy (Directly Used for Alibaba / Echemi)
Product Title
n-Butyl Isocyanate n-BIC CAS 111-36-4 99% Colorless Fuming Liquid Isocyanate Intermediate for Pharmaceutical Peptide Synthesis Agrochemical Urethane Coating
Short Description
n-Butyl Isocyanate (C₅H₉NO, CAS 111-36-4) ≥99% anhydrous high-activity aliphatic monoisocyanate liquid, sensitive to moisture. Widely used as key intermediate for solid-phase peptide synthesis, heterocyclic pharmaceutical APIs, urea herbicides and polyurethane coating crosslinkers. Full set of dangerous goods export documents including COA, MSDS and TDS available for global bulk shipment.
Full Listing Description
n-Butyl Isocyanate (abbreviated n-BIC, CAS 111-36-4) is a high-reactivity aliphatic monoisocyanate supplied as colorless transparent fuming liquid with GC purity ≥99.0%. Its active -NCO group can undergo quantitative addition reaction with hydroxyl, amino groups to synthesize carbamate and urea derivatives, which are irreplaceable building blocks for fine chemical manufacturing.
Main downstream application sectors cover high-end pharmaceutical raw material and peptide amino-protecting reagent; agrochemical urea fungicide & herbicide intermediate; polyurethane flexible coating and single-component blocked isocyanate crosslinker; laboratory selective acylation synthesis reagent. We supply standard industrial grade and ultra-high purity pharmaceutical special grade with ultra-low moisture and amine impurities, packed under nitrogen to avoid hydrolysis during long sea transportation.
All products adopt nitrogen-sealed lined steel drums for full container shipment. Classified as UN2485 triple-hazard dangerous goods (flammable, toxic, corrosive), we provide complete official customs clearance certification documents to support global sea and land delivery with stable continuous mass supply capacity.
7. Printable Export COA Template
CERTIFICATE OF ANALYSIS
Product Name: n-Butyl Isocyanate (n-BIC)
CAS No.: 111-36-4
Grade: Export Premium Industrial Grade
Batch No.: ____________
Net Weight: 200kg/drum
Manufacture Date: ___________
| Test Item | Standard Spec | Test Result | Test Method |
| n-Butyl Isocyanate Assay Purity | ≥99.0 % |
| GC Gas Chromatography |
| Free n-Butylamine Impurity | ≤0.10 % |
| GC Titration |
| Urea Dimer Hydrolysis Residue | ≤0.30 % |
| GC |
| Moisture Content | ≤50 ppm |
| Karl Fischer Titration |
| Color (APHA) | ≤30 |
| Platinum-Cobalt Colorimetry |
| Distillation Range (113–117℃) | ≥95 vol% |
| Distillation Test |
| Appearance | Colorless clear fuming liquid without turbidity or sediment | Visual Inspection |
|
Conclusion: This batch meets premium export industrial standard of n-Butyl Isocyanate.
Inspector Signature: ____________
Testing Date: ____________
India
United Kingdom
