Clean machines from beans
What do industrial cleaners, paint solvents, diesel fuel, and nail polish remover have in common? They can all be produced using soybean-derived esters.
Congress established the United Soybean Board (USB) in 1991 to create greater demand for and increase the value of soybeans. It is a producer-run organization that funds growth development by investing checkoff program revenues generated by the sale of soybeans. In the checkoff program, 0.05% of soybean revenue in the United States is shared equally by the USB and the soybean boards of the producing states.
The effort to develop and commercialize new soy-based products is a very broad program involving industry, universities, private research organizations, and government agencies. As a result, dozens of industrial companies are producing and marketing numerous new products that compete effectively with existing petroleum-based chemical products.
The focus of industrial product development has been on five primary market segments:
New commercial products that have been introduced include finger-joint wood glues, urethane polyols, interior trim paints, plastic composites, printing inks, metalworking fluids, specialty lubricants, and industrial solvents. The majority of these products are made from soybean oil, one of the most plentiful and least expensive sources of fatty acids. It is renewable and provides many environmental benefits as a chemical feedstock, including biodegradability and low toxicity.
Methyl soyateproperties and applications
From a performance standpoint, methyl soyate provides effective solvency, is low in volatile organic compounds (VOCs), has a high flashpoint, is nontoxic, and is compatible with other organic solvents and most metals, plastics, and elastomers. Its principal properties are shown in Table 1. Despite its good solvent properties, methyl soyate is typically not used neat because it evaporates slowly and leaves residual film on surfaces. In most applications, it is formulated with cosolvents or surfactants to meet specific performance requirements. Slow evaporation can be an advantage in many applications, such as ink removal and paint stripping, by extending the duration of solvent action and reducing solvent usage.
When its VOC content is compared with other solvents, methyl soyate is clearly preferable from an environmental standpoint (Figure 3 at right). Likewise, its flash point is considerably higher than those of competitive solvents (Figure 4 at right). These properties make methyl soyate a safe, environmentally friendly alternative for chlorinated, petroleum-based, and oxygenated solvents in many industrial applications.
Creative specialty chemical formulators have recently launched several new industrial and consumer products that use methyl soyates solvent properties and cosolvent compatibility. These products are designed for problem market applications requiring safe solvent replacement.
The primary market application for methyl soyate, which takes advantage of its solvent properties, is industrial cleaning and degreasing. Methyl soyate works well in products formulated with cosolvents or surfactants to accelerate drying and water rinsing. Methyl soyate can help to replace environmentally unfavorable petroleum and chlorinated solvents in basic parts cleaning. Formulations with other cosolvents such as ethyl lactate work well in the more stringent cleaning processes used in the electronics and aerospace industries. Other potential uses are in ultrasonic cleaning, household cleaners, food processing industries, and asphalt handling.
Resin removal and cleanup is a broad category with many cosolvent products currently in the field evaluation stage, especially in paint strippers, printing ink cleaners, and equipment cleaners. Field trials are under way on military aircraft and ships and at many major newspapers. Adhesive and anti- graffiti products containing methyl soyate are widely used.
Ethyl lactate, used neat, is a strong solvent, but it has a relatively high VOC content and a low flash point. The blend ameliorates both properties of ethyl lactate and improves the drying rate, residue deposition, and water rinsability of methyl soyate. Blending also lowers the cost compared with straight ethyl lactate. Both solvents are derived from crops, so they are renewable as well as biodegradable. Vertec Biosolvents patents on the composition and use of the blends were issued in 2000.
Vertec Gold was recently tested and evaluated by Argonne National Laboratory for parts cleaning and degreasing in their Central Shops. A summary from the pilot project report is given in the box, Testing Vertec Gold (6).
Cleaning up oil spills
The selection process used by CytoCulture to develop the most effective solvent medium for oil spill remediation involved finding the right combination of performance properties, petroleum solvency, specific gravity, recoverability, and biodegradability. Methyl soyate was identified as having the best combination of these properties, and the CytoSol process was developed to enhance its performance.
The CytoSol process is a two-step cleanup technology for removing spilled oil accumulated on shorelines, breakwaters, piers, riverbanks, and other waterway structures. In the first step, the process uses a vegetable-oilbased biosolvent containing methyl soyate to release and recover the weathered petroleum. The CytoSol process expedites the removal of spilled oil through the specific physical and chemical changes it imparts to the petroleum, such as
In laboratory simulations and field trials, the CytoSol process was found to release 5090% of the original oil adhering to or trapped in various shoreline sediments ranging from riparian vegetation and fine estuary sands to coarse California beach sand and gravel in Prince William Sound. This first step required only a single CytoSol application followed by extensive washing with ambient-temperature seawater to flush out the floating oilCytoSol mixture. In the second step, the remaining CytoSol biosolvent and residual petroleum hydrocarbons are degraded by bacteria present at the site. The bacterial action is supplemented by a program of nutrient enhancement and oxygenation. Following the formulation and application development of the CytoSol process, the biosolvent was subjected to thorough testing for marine toxicity, marsh plant survival, and biodegradation under the guidance of several state and federal environmental agencies to achieve EPA listing and California licensing.
Many more applications
One of the early applications for methyl soyate was in fuels and lubricants. Numerous lubricant products are being marketed or are in development, including household lubricant sprays, metalworking fluids, form-release agents for asphalt, and concrete and lubricity additives.
The primary commercial fuel product is biodiesel. It has been in development since the late 1980s and was recognized last year by an act of Congress as the only alternative fuel to meet the performance requirements of the Clean Air Act of 1990. As a straight fuel, it reduces airborne toxins by 90%, compared with standard diesel fuel and it provides excellent lubricity for extending engine life, replacing sulfur compounds. Because of its high cost, it is typically used as a 20% blend (B-20) with petroleum-based diesel. Commercial use in bus and truck fleets in the United States is growing because of the recent surge in fuel prices. The similar use of grapeseed-based methyl esters as biodiesel fuels is even greater in Europe.
Many new methyl-soyatebased products have been introduced into the consumer products area. On the basis of its environmentally friendly properties (low toxicity, low VOCs, and biodegradability) and the growing interest in renewable ingredients, the use of soy methyl esters is increasing in products such as hand cleaners, skin lotions, nail polish removers, and auto polishes.
The environmental, product performance, and economic advantages of soy-based derivatives such as methyl soyate for industrial and consumer applications have created widespread interest and support from private industry and government agencies for the replacement of petrochemicals. As a result, technical and commercial development of these products continues to grow.
The soybean is a natural, annually renewable feedstock for industry. Work supported by the United Soybean Boards New Uses Program by universities, government agencies, and industrial companies is creating significant results.
Stephen G. Wildes is a commercialization manager at Omni Tech International Ltd. (2715 Ashman St., Midland, MI 48640; 517-631-3377, ext. 235; email@example.com). He received his B.S. in geology and his M.B.A. from the University of Michigan, Ann Arbor. He was with Dow Chemical Co., Midland, MI, for 25 years in business and marketing management for industrial chemicals, plastics, and membrane separation systems. He can be contacted for more information, supplier contacts, and a list of commercial products.
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