Formulation of Environmentally Safe Graffiti Remover Containing Esterified Plant Oils and Sugar Surfactant

• Published in: Molecules (Basel, Switzerland) Switzerland), 2021-08, Vol.26 (15), p.4706
• Main Authors: Bartman, Marcin, Balicki, Sebastian, Wilk, Kazimiera A.
• Format: Article
• Language: English
• Subjects: Biocompatibility; Biodegradability; Biodegradation; Catalysts; Cleaning; Contact angle; Cooking; Cooking oils; Cultural heritage; Design optimization; eco-friendly graffiti remover; environmentally friendly; Esterification; esterified plant oils; Ethyl lactate; formulation optimization; Formulations; Graffiti; Green chemistry; green solvents; Lactic acid; Monobutyltin; Optimization; Paints; Petroleum; Petroleum ether; Pollutants; Porous materials; Rapeseed; Rapeseed oil; Raw materials; Response surface methodology; Sandstone; Solvents; sugar surfactants; Sunflower oil; Sunflowers; Surfactants; Sustainable development; Toluene; Transesterification
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26154706

The removal of graffiti or over-painting requires special attention in order to not induce the surface destruction but to also address all of the important eco-compatibility concerns. Because of the necessity to avoid the use of volatile and toxic petroleum-based solvents that are common in cleaning formulations, much attention has recently been paid to the design of a variety of sustainable formulations that are based on biodegradable raw materials. In the present contribution we propose a new approach to graffiti cleaning formulations that are composed of newly synthesized green solvents such as esterified plant oils, i.e., rapeseed oil (RO), sunflower oil (SO), or used cooking oil (UCO), ethyl lactate (EL), and alkylpolyglucosides (APGs) as surfactants. Oil PEG-8 ester solvents were synthesized through the direct esterification/transesterification of these oils using monobutyltin(IV) tris(2-ethylhexanoate) and titanium(IV) butoxide catalysts under mild process conditions. The most efficient formulations, determined by optimization through the response surface methodology (RSM) was more effective in comparison to the reference solvents such as the so-called Nitro solvent (denoting a mixture of toluene and acetone) and petroleum ether. Additionally, the optimal product was found to be effective in removing graffiti from glass, metal, or sandstone surfaces under open-field conditions in the city of Wrocław. The performed studies could be an invaluable tool for developing future green formulations for graffiti removal.