Ethynylcyclopropane

Ethynylcyclopropane is an organic compound with the molecular formula C5H6 and CAS number 6746-94-7. This cyclic hydrocarbon features a three-membered cyclopropane ring with an attached ethynyl group (acetylene functionality). With a molecular weight of 66.1 g/mol, it represents a highly strained and reactive molecule due to the combination of cyclopropane ring tension and the triple bond functionality, making it valuable in specialized organic synthesis applications.

Ethynylcyclopropane is a volatile organic liquid at room temperature with high flammability characteristics. The compound exhibits typical properties of strained cyclic acetylenes, including reactivity toward addition reactions. Its low molecular weight (66.1 g/mol) and hydrocarbon structure suggest limited water solubility but good solubility in organic solvents. The presence of both cyclopropane strain and acetylene functionality makes it thermodynamically unstable and prone to polymerization or rearrangement reactions.

Ethynylcyclopropane is primarily used as a specialized building block in organic synthesis and pharmaceutical research. Its unique structural features make it valuable for preparing complex cyclic compounds through ring-opening reactions and cycloaddition processes. The compound serves as an intermediate in the synthesis of bioactive molecules and specialty chemicals. Its reactivity profile makes it particularly useful in academic research for studying strained ring systems and developing new synthetic methodologies.

Ethynylcyclopropane requires careful handling due to its flammable nature and potential for skin and eye irritation. Personal protective equipment must include chemical-resistant gloves, safety goggles, and appropriate clothing to prevent skin contact. Work should be conducted in well-ventilated areas or under fume hoods, away from ignition sources. The compound can cause severe eye damage and skin irritation, requiring immediate attention if contact occurs. Ground all equipment to prevent static electricity buildup.

Ethynylcyclopropane must be stored in a cool, dry, well-ventilated area away from heat sources, sparks, and open flames. Keep containers tightly sealed and use appropriate secondary containment. Store separately from oxidizing agents, acids, and bases due to potential incompatibilities. Temperature control is essential to prevent decomposition or polymerization. Use explosion-proof electrical equipment in storage areas and maintain proper grounding. Regular inspection of containers for leaks or deterioration is recommended.

Ethynylcyclopropane contact requires immediate action due to its irritating properties. For skin contact, immediately remove contaminated clothing and flush the affected area with plenty of water for at least 15 minutes. In case of eye contact, rinse immediately with water for at least 15 minutes and seek immediate medical attention as the compound can cause severe eye damage. If inhaled, move the person to fresh air immediately. Seek medical attention for all exposure incidents.

Ethynylcyclopropane disposal must comply with local, national, and EU waste regulations as a hazardous chemical waste. The compound cannot be disposed of in regular waste streams due to its flammability and environmental impact. Contact licensed hazardous waste disposal companies for proper treatment, which typically involves incineration at high temperatures in specialized facilities. Small quantities may require neutralization or reaction to less hazardous compounds before disposal. Always consult current waste disposal regulations and safety data sheets.

Ethynylcyclopropane is classified as ADR Class 3 (flammable liquids), Packing Group II, indicating moderate danger level for transport. Transportation requires appropriate UN-specification packaging designed for flammable liquids. Vehicles must carry proper placarding and documentation, and drivers need ADR certification. The compound requires segregation from incompatible materials during transport. Emergency response information must accompany shipments, and transport should avoid extreme temperatures to prevent vapor pressure buildup or decomposition.

Ethynylcyclopropane is subject to standard EU chemical regulations including REACH registration requirements and CLP classification. The compound is classified under GHS with specific hazard categories (Flam. Liq. 2, Skin Irrit. 2, Eye Dam. 1, Aquatic Chronic 3) requiring appropriate labeling and safety data sheets. It is not currently listed as a Substance of Very High Concern (SVHC). Users must comply with occupational exposure limits and industrial emissions regulations where applicable.

Ethynylcyclopropane is available through OYSI, a specialized European distributor of technical chemicals serving research institutions and industrial customers. As a niche specialty chemical, it requires sourcing from suppliers experienced in handling reactive compounds. OYSI provides proper documentation, safety data sheets, and regulatory compliance support for European customers. Due to its specialized nature and handling requirements, availability may be subject to minimum order quantities and lead times for custom synthesis or importation.