Integrated Catalytic Process for Converting Waste Cooking Oils into High-Performance Advanced Biolubricants

Background

The field of biolubricants has gained increasing attention due to the need for sustainable and environmentally friendly alternatives to conventional petroleum-based lubricants. Waste cooking oils (WCOs) represent an abundant and renewable resource that can be valorized into high-value products, reducing environmental pollution and reliance on fossil resources. Traditional vegetable oils, while biodegradable and possessing good lubricity, are limited in their direct application as lubricants due to issues such as thermal instability and susceptibility to oxidation. Furthermore, using virgin vegetable oils for industrial purposes raises concerns about competition with the food supply chain, making the utilization of WCOs a more sustainable and economically viable approach for producing bio-based lubricants.

Current approaches to producing biolubricants from WCOs or vegetable oils typically involve minimal chemical modification, such as transesterification or simple blending, which fails to address the inherent limitations of these feedstocks. Vegetable oil-based lubricants often suffer from poor oxidative stability, low viscosity index, and inadequate performance at low temperatures, leading to rapid degradation and limited applicability in demanding industrial settings. Additionally, these oils exhibit poor additive solubility and can form undesirable byproducts such as free fatty acids, which increase acidity and promote polymerization during use. As a result, existing biolubricants do not meet the performance standards required for many industrial and automotive applications, highlighting the need for advanced processes that can tailor molecular structures and enhance the physicochemical properties of biolubricants derived from waste oils.

Technology

This technology enables the transformation of waste cooking oils (WCOs) and cyclic oxygenated hydrocarbons (COHCs) such as biomass pyrolysis oil into advanced biolubricants through a sophisticated, four-step catalytic process. The process begins with the hydrolysis of WCO triglycerides into free fatty acids (FFAs), which are then subjected to dehydration and ketonization to form condensation products such as anhydrides and ketones. These intermediates are further reacted with COHCs via Friedel-Crafts acylation/alkylation, introducing cyclic and aromatic structures into the hydrocarbon chains. The final hydrotreatment step saturates double bonds and reduces oxygen content, resulting in biolubricants with tailored molecular architectures that combine long linear chains with cyclic and aromatic rings. This integrated approach, utilizing heterogeneous catalysts, yields lubricants with enhanced oxidative stability, high viscosity index, improved low-temperature performance, and robust thermal stability.

What differentiates this technology is its comprehensive and integrated catalytic pathway, which overcomes the core limitations of traditional vegetable oil-based lubricants—namely, poor oxidative stability, low viscosity index, and inadequate low-temperature behavior. By leveraging waste cooking oils as a renewable feedstock, the process not only addresses sustainability and waste valorization but also avoids competition with the food supply. The sequential use of specialized catalysts at each stage enables precise molecular tailoring, resulting in biolubricants with superior physicochemical properties, including low pour points, high viscosity indices, and excellent additive compatibility. The final products exhibit performance metrics that meet or exceed those of commercial mineral and synthetic lubricants, while also being biodegradable and environmentally friendly.

Benefits

• Transforms low-value waste cooking oils into high-performance biolubricants, promoting sustainability and waste valorization.
• Produces lubricants with enhanced oxidative and thermal stability, extending lubricant life and reliability.
• Achieves high viscosity index and tailored molecular structures combining linear and cyclic/aromatic chains for superior lubrication.
• Improves low-temperature performance with low pour points, ensuring fluidity in cold environments.
• Utilizes an integrated catalytic process with heterogeneous catalysts, enabling efficient, scalable, and potentially reusable catalyst systems.
• Delivers biolubricants with good additive solubility and boundary lubrication due to polar functional groups.
• Results in biodegradable, non-toxic lubricants suitable for industrial, engine, and specialty applications with improved environmental profiles.

Applications

• Industrial machinery lubricants
• Automotive engine oils
• Hydraulic fluids
• Biodegradable specialty lubricants

Additional info

This technology transforms waste cooking oils and cyclic oxygenated hydrocarbons into advanced biolubricants. An integrated four-step catalytic process modifies molecular structures, introducing cyclic and aromatic rings into long hydrocarbon chains. This yields high-performance lubricants with enhanced oxidative/thermal stability, a high viscosity index, and improved low-temperature properties.