PROCESS TO OBTAIN MIXTURES OF IMIDAZOLINES AND CORROSION INHIBITORS FROM COFFEE WASTE

The biphasic extraction from coffee waste without a prior drying process, to obtain coffee oil, which is transesterified with KOH catalyzed methanol to produce mixtures of glycerol free methylic esters, also known as coffee oil biodiesel, which is subjected to an aminolysis reaction with aminoethylethanolamine (AEEA) by heating to 140-160 DEG C. at atmospheric pressure with a subsequent dehydration reaction at the same temperature but at a reduced pressure of 200 to 300 mmHg, in order to achieve cyclization of the intermediary amides into the corresponding imidazolines. Alternatively process, coffee oil can be submitted to the same aminolysis procedure with aminoethylethanolamine (AEEA) at 140 to 160 DEG C. and atmospheric pressure with a subsequent dehydration reaction at the same temperature but at a reduced pressure of 200 to 300 mmHg, to produce imidazolines that contain the residual glycerol of the original triglycerides. The imidazolines mixtures obtained by any of the two alter native processes present a high performance as corrosion inhibitors. The imidazolines mixtures obtained according to the present invention are characterized in that they contain a high grade of unsaturation in the alkyl chains, which provides a higher adherence to the metallic surfaces than saturated imidazolines. This imidazoline mixture constitutes a corrosion inhibitor of high performance, low toxicity and suitable biodegradability. La presente invención consiste en la extracción bifásica del café de desecho sin secado previo para obtener, después de concentración de la fase hidrocarbonada, el aceite de café, el cual es transferido con metanol catalizado con KOH para producir mezclas de ésteres metílicos libres de glicerol, también llamado biodiesel de aceite de café, el cual se somete a una reacción de aminólisis con la aminoetiletanolamina (AEEA) entre 140-160 °C a presión atmosférica con posterior deshidratación por calentamiento a la misma temperatura pero con presión reducida a 200-300 mmHg, para realizar la ciclación de las amidas intermediarias a las correspondientes imidazolinas. En un proceso alternativo, el aceite de café puede ser sometido al mismo proceso de aminólisis con la aminoetiletanolamina (AEEA) entre 140-160 °C a presión atmosférico con posterior deshidratación por calentamiento a la misma temperatura pero con presión reducida a 200-300 mmHg, para producir mezclas de imidazolinas que contienen el glicerol residual de los triglicéridos originales. Las m