Study On The Preparation Of Organic Acid Gelling Agent And Its Oil Coagulation Performance

The world has been facing the problem of marine pollution caused by oil spills.At present,cleaning methods such as adsorption,combustion,oil absorbent,dispersant,oleophage microorganism or nutrient degradation are not economically feasible solutions on a large scale.Phase-selective organic gelators PSOGs,which can selectively condense oil from a two-phase mixture of water and oil,are considered to be a potential and effective method to solve this problem.Most of the PSOGs reported so far require carrier solvent for solubilization.In this paper,three kinds of organic acid gelling agents with different groups were explored to realize the gelation of light oil and organic solvent in dry powder state.A kind of compound gelation system based on aluminum naphthenate was designed and synthesized.Aluminum naphthenate was compounded with fatty acid or fatty acid aluminum,and room temperature gelation experiments were carried out with kerosene as the main solvent.The two-component gelation system AN-SA with the best ratio of 4:1 was comprehensively selected.The AN-SA dry powder can achieve specific gelation at ultra-low gelation concentration for kerosene,and the complete gelation concentration is only0.025g/m L.The rheological test shows that the gel has high viscoelasticity,certain strength and instantaneous resilience,and the thermal stability of the gel is high.Combined with the analysis of the mechanism of gel formation by infrared spectroscopy and X-ray diffraction,it was found that hydrogen bond became the most important driving force.In addition,there was also a crosslinking effect between fatty acid and kerosene in the compound system of aluminum naphthenate and fatty acid,thus improving the gelling oil performance.In order to further explore the oil coagulation potential of organic acid gelling agent,another type of organic acid gelling agent was prepared by amidation reaction of aromatic carboxylic acid with primary amine.The β-phenylacrylic acid-based gelling agent was prepared by the reaction of β-phenylacrylic acid with hexadecylamine.The gelation test was carried out in 10 solvents,and four gel systems of kerosene,diesel oil,vegetable oil and xylene were selected.The minimum gelation concentration in kerosene,diesel oil and vegetable oil was 0.05g/m L.The thermal stability of the three oleogels was tested.It was found that the thermal stability of the vegetable oil gel was the highest,and the phase transition temperature of the gel-sol could be as high as 190 °C,followed by the diesel oil gel.The rheological test of the diesel gel by frequency scanning found that the G′ storage modulus value is more than an order of magnitude higher than the G″ loss modulus,indicating that the gel has better viscoelastic properties.The internal structure of the gel was found to be fibrous or flaky after scanning electron microscopy analysis represented by kerosene and xylene.The role of non-covalent bonds in the self-assembly of the gel to form a three-dimensional network structure was studied by infrared spectroscopy and X-ray diffraction.Studies have shown that the amide group,the hydrogen bond provided by the carbonyl group,the van der Waals force provided by the alkyl chain,and the π-π stacking provided by the benzene ring play the most important driving role.In order to explore the difference in gelation properties of similar gelling agents,β-phenylacrylic acid was replaced with p-hydroxybenzoic acid containing para-hydroxyl group,and then reacted with hexadecylamine to prepare a new gelling agent.The minimum concentration of complete gelation of the new gelling agent in xylene is 0.05 g/m L.The gelation concentration of kerosene,diesel oil and vegetable oil is different.The viscoelasticity of the gel formed in vegetable oil is the highest,and the microstructure is denser.In the mechanism analysis,it was found that in addition to the hydrogen bonds provided by the amide group,there were also hydrogen bonds provided by the hydroxyl group.It can be concluded that the p-hydroxybenzoic acid-based gelling agent has specific gelling ability for some organic solvents,and the gelling effect is better for slightly viscous light oil.