Este trabalho apresenta os resultados de um estudo sobre o uso da água subcrítica, como reagente e solvente, para a reação de hidrólise de óleo de milho sem o emprego de ácidos e base entre as temperaturas de 150-280 °C. A hidrólise de óleo de milho leva à formação dos seus respectivos ácidos graxos, com a mesma eficiência dos métodos convencionais. Os ácidos graxos formam um grupo importante de produtos, os quais são usados em diversas aplicações. A identificação e confirmação dos produtos da hidrólise foram feitos por HT-HRGC-FID e HRGC/MS. This work presents the results of a study on the use of subcritical water as both solvent and reactant for the hydrolysis of corn oil without the use of acids or alkalis at temperatures of 150-280 °C. Corn oil hydrolysis leads to the formation of its respective fatty acids with the same efficiency of conventional methods. Fatty acids form an important group of products, which are used in a range of applications. The confirmation and identification of the hydrolysis products was done by HT-HRGC-FID and HRGC/MS. Keywords: subcritical water, hydrolysis, fatty acids, corn oil IntroductionThe development of methodologies environmentally friend has been one of the principal objectives pursued by researchers of several areas as chemistry, process development and others. Ideally, the absence of organic solvents is a factor of major importance in any process, because they should be recycled, incinerated or submitted to an appropriate unitary operation that does not result in aggression to the environment.Water in the sub or supercritical state presents unusual properties that have been raising a lot of interest as an alternative solvent. [1][2][3][4] Many studies have been done exploring the use of water in conditions sub and supercritical to promote organic synthesis reactions, some of those would be alkyl-aromatics oxidation, oxidation of methane in hydrothermal systems, dehydration of alcohol, and organic transformations catalyzed by metals. 1 Another option is the employment of subcritical water as both solvent and reagent for triglycerides hydrolysis. 5 Some studies utilizing pressures higher than 2 MPa and temperature over 250 °C, demonstrate the viability of its use without the need of using either acidic or alkaline catalysts.Hydrolysis of oils is the applied term to the operation in which water reacts with oil to form glycerol and fatty acids. 6 This process is commercially important because the fatty acids are used for soap production, synthetic detergents, greases, cosmetics, and several other products. [7][8][9] The soap production starting from triglycerides and alkalis is accomplished for more than 2000 years by the Man. 10 where C 3 H 5 (OCOR) 3 represents triglycerides, RCOOH represents any fatty acid and C 3 H 5 (OH) 3 , glycerol.Several authors propose that this reaction is processed in stages, starting from the triglycerides for diglycerides, monoglycerides and glycerol, and to each stage there is liberation of a fatty acid. This reaction is homogeneous of first o...

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Este trabalho descreve a construção e teste de um sistema simples de extração pressurizada com solvente (PSE). Uma mistura de acetona:água (80:20), a 80 ºC e 103,5 bar, foi utilizada para extrair dois herbicidas (Diuron e Bromacil) de uma amostra de solo contaminado. Os herbicidas foram identificados e quantificados por cromatografia líquida de alta eficiência acoplada a detector por arranjo de diodos (HPLC-DAD). O sistema também foi utilizado para extrair óleo de soja (70 ºC e 69 bar) empregando pentano como solvente. O óleo extraído foi pesado e caracterizado através da análise dos ésteres metílicos dos ácidos graxos (ácidos mirístico (< 0,3%), palmítico (16,3%), esteárico (2,8%), oléico (24,5%), linoléico (46,3%), linolênico (9,6%), araquídico (0,3%), gadolêico (< 0,3%) e behênico (0,3%)) por cromatografia gasosa de alta eficiência com detecção por ionização em chama (HRGC-FID). Os resultados do sistema PSE foram comparados com os determinados pelos procedimentos tradicionais, ou seja, extração soxhlet para o óleo de soja e extração sólido-líquido seguida da extração em fase sólida (SLE-SPE) para os herbicidas no solo. Com o sistema PSE determinou-se 21,25 ± 0,36% (m/m) de óleo na soja, já com soxhlet 21,55 ± 0,65% (m/m). Para a extração dos herbicidas Diuron e Bromacil, utilizando o sistema PSE, a eficiência (recuperação) foi de 88,7 ± 4,5% e 106,6 ± 8,1%, respectivamente. Já com o sistema SLP-SPE obteve-se 96,8 ± 1,0% e 94,2 ± 3,9%. Os limites de detecção (LOD) e de quantificação (LOQ) para Diuron foram 0,012 mg Kg -1 e 0,040 mg Kg . O sistema PSE, devido à alta pressão e temperatura, possibilita extrações com consumo de solvente reduzido, eficientes, rápida, e uma atmosfera inerte a qual preserva as amostras e os analitos da decomposição.This work describes the construction and testing of a simple pressurized solvent extraction (PSE) system. A mixture of acetone:water (80:20), 80 ºC and 103.5 bar, was used to extract two herbicides (Diuron and Bromacil) from a sample of polluted soil, followed by identification and quantification by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The system was also used to extract soybean oil (70 ºC and 69 bar) using pentane. The extracted oil was weighed and characterized through the fatty acid methyl ester analysis (myristic (< 0.3%), palmitic (16.3%), stearic (2.8%), oleic (24.5%), linoleic (46.3%), linolenic (9.6%), araquidic (0.3%), gadoleic (< 0.3%), and behenic (0.3%) acids) using high-resolution gas chromatography with flame ionization detection (HRGC-FID). PSE results were compared with those obtained using classical procedures: Soxhlet extraction for the soybean oil and solid-liquid extraction followed by solid-phase extraction (SLE-SPE) for the herbicides. The results showed: 21.25 ± 0.36% (m/m) of oil in the soybeans using the PSE system and 21.55 ± 0.65% (m/m) using the soxhlet extraction system; extraction efficiency (recovery) of herbicides Diuron and Bromacil of 88.7 ± 4.5% and 106.6 ± 8.1%, respectively, using the PSE ...

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