جستجوی مقالات مرتبط با کلیدواژه "اولئیک اسید" در نشریات گروه "شیمی"

At first, inorganic powders including pine cone ash, micronized silica and alumina were coated with oleic and stearic acid in technical grade solvents including ethanol (96%) and toluene under heat treatment. Then, the different amounts of each coated powders and their mixture were used to modify the bitumen. Different properties of the modified bitumens including penetration rate, softening point, and the results of dynamic shear rheometer (DSR), bending beam rheometer (BBR), and multiple stress creep recovery (MSCR) tests were compared with the pure bitumen sample. The results showed that the penetration rate is increased with increasing of the percentage of the coated additives. In addition, the softening point of the pure bitumen sample has no significant change with addition of the coated powders. This phenomenon is an advantage in the modification of bitumen. The results of DSR test showed that the maximum total shear stress modulus (G*) at three different temperatures is related to the silica sample coated with oleic acid. The results of BBR test showed that the maximum creep hardness at -6 and -12°C is related to 4% silica coated with oleic acid and 2% pine cone ash coated with stearic acid, respectively. The MSCR test indicated that the maximum recovery percentage in a stress of 100 and 3200 Pa was observed for 2% silica coated with stearic acid and 4% pine cone ash coated with stearic acid, respectively

Nowadays, smartphones and their software play an important role in facilitating the teaching-learning process. Some of these softwires can help a lot in performing tests or analyzing their results. In this study, using a mobile application software, after taking a picture of the surface of the container on which the oil was spread, the Avogadro number was determined by determining the thickness of the oleic acid monolayer. This method of measuring the Avogadro number by imaging the oil stain with a mobile phone and then calculating its level by the software, compared to other physical methods of determining the oil area (such as drawing a shape on glass and then paper) in less time and more accurately is possible. This calculates the area of ​​the oleic acid monolayer accurately. In this method, while performing the classical experiment of measuring Avogadro number by counting method, which is necessary for students' deep understanding of this important physical constant, it is possible to increase the accuracy of calculations and reduce the measurement steps.

Phase equilibrium systems are important topics in physical chemistry. As the practical training of phases contributes to a deeper understanding of this part of science, planning an agenda with a green chemistry approach and attention to human health is essential. In this study, a simple solid-liquid phase equilibrium system, palmitic acid - oleic acid, replaced the naphthalene - benzene or naphthalene - toluene system. This system not only can this system meet the educational goals of this department, but it also has the capability to recycle consumables and use waste as raw materials in other training laboratories. It is also affordable for an undergraduate training lab. From this simple experiment, the melting point of palmitic acid was 64° C and the melting enthalpy of this material was 40.69 kJ / mol. Compared to the actual values, due to the simple tools and the purity of the material used, it has an acceptable error percentage. It is noteworthy that the same uncertainty also is observed in the results of naphthalene-toluene system.