1. Chemical Structure and Properties

Molecular Formula: C₁₄H₂₆O₄
      Structural Formula:
      CH₂CH(CH₂OCO(CH₂)₄COOCH₂CH(CH₃)₂)₂
      A diester formed by the esterification of adipic acid with two isobutyl alcohol molecules.

Physical Properties:
     Appearance: Clear, colorless to pale yellow oily liquid with a faint ester-like odor.
     Boiling Point: 305–310°C; Density: 0.95–0.97 g/cm³; Vapor Pressure: <0.01 mmHg at 25°C.
     Solubility: Insoluble in water; miscible with alcohols, esters, and most organic solvents.

Chemical Properties:
     Hydrolysis Stability: Resistant to hydrolysis under neutral conditions; degrades in strong acids/bases to adipic acid and isobutanol.
     Thermal Stability: Stable up to 200°C; decomposes above 250°C, releasing CO₂ and hydrocarbons.
     Flammability: Combustible (flash point: ~150°C).

2. Industrial Applications

Plasticizers:
     PVC & Polymers: Primary plasticizer for flexible PVC products (e.g., cables, films) due to low volatility and compatibility.

Cosmetics:
     Emollient & Solvent: Used in lotions, creams, and nail polish for its non-greasy texture and skin adhesion.

Lubricants:
     Synthetic Base Oil: Enhances low-temperature performance in industrial lubricants.

Chemical Synthesis:
     Intermediate: Produces specialty esters for adhesives and coatings.

3. Safety and Toxicology

Health Hazards:
     Acute Exposure:
     Skin Contact: Mild irritation (rabbit skin LD₅₀: >5,000 mg/kg); negligible absorption.
     Inhalation: Low volatility minimizes risk (TLV-TWA: Not established).
     Ingestion: Low toxicity (oral LD₅₀ rat: >10,000 mg/kg); gastrointestinal discomfort.

Chronic Effects:
     Carcinogenicity: Not classified (IARC Group 4); no mutagenicity in Ames tests.
     Reproductive Toxicity: No teratogenicity observed in OECD 415 studies.

Protection Measures:
     PPE: Nitrile gloves and safety goggles; general ventilation for handling.
     Storage: Stable in HDPE containers; store away from oxidizers.

4. Environmental and Regulatory Compliance

Environmental Impact:
     Biodegradability: Moderate (OECD 301F: 40–60% in 28 days).
     Aquatic Toxicity: LC₅₀ (fish, 96h): >100 mg/L; EC₅₀ (daphnia): >50 mg/L.
     Bioaccumulation: Low (log Kow: ~4.5).

Regulatory Frameworks:
     EU:
     REACH: Registered with no SVHC listing; CLP classification Not Hazardous.
     USA:
     EPA: TSCA-listed; approved for cosmetics under FDA 21 CFR 700.
     China:
     GB 13690-2009: Classified as General Chemical (non-hazardous).

Waste Management:
     Incinerate in approved facilities; landfill disposal permitted for neutralized residues.

5. Case Studies and Application Insights

Case 1: Phthalate-Free PVC Toys (LEGO, 2022):
     Challenge: Replace phthalates in children’s toys with safer plasticizers.
     Solution: Diisobutyl adipate adopted as a primary plasticizer in flexible PVC parts.
     Result: Achieved EU Toy Safety Directive compliance and reduced toxicity risks by 90%.

Case 2: High-Performance Cosmetic Formulations (L’Oréal, 2023):
     Innovation: Formulated long-wear nail polish using diisobutyl adipate as a film-forming agent.
     Impact: Enhanced durability (24-hour wear) and reduced solvent content by 30%.

Comparative Analysis:
     Diisobutyl Adipate vs. DEHP:
     Pros: Lower endocrine disruption risk; better biodegradability.
     Cons: Higher cost and slightly lower plasticizing efficiency.
     Diisobutyl Adipate vs. DINCH:
     Pros: Superior compatibility with PVC; faster processing times.
     Cons: DINCH offers lower migration rates in food-contact applications.

Specifications:
Diisobutyl adipate is a fatty acid ester. ChEBI. Diisobutyl adipate is a natural product found in Gymnodinium nagasakiense and Karenia mikimotoi with data available. LOTUS - the natural products occurrence database.