The study involved the removal of acidity from free fatty acid via the esterification reaction of oleic acid with ethanol. The reaction was done in a batch reactor using commercial 13X zeolite as a catalyst. The effects of temperatures (40 to 70 °C) and reaction time (up to 120 minutes) were studied using 6:1 mole ratio of pure ethanol to oleic acid and 5 wt. % of the catalyst. The results showed that acid removed increased with increasing temperature and reaction time. Also, the acidity removal rises sharply during the first reaction period and then changes slightly afterward. The highest acidity removal value was 67 % recorded at 110 minutes and 70 °C. An apparent homogeneous reversible reaction kinetic model has been proposed and solved with the experimentally obtained kinetics data to evaluate reaction rate constants versus temperature, pre-exponential factors, and activation energy values for the forward and the backward esterification reactions. The activation energies were 34.863 kJ/mol for the forward reaction and 29.731 kJ/mol for the backward reaction. The thermodynamics of the activation step of the forward and reverse reactions was studied based on the hypothesis of forming a complex material that decomposes into a product. The activation steps were studied using Eyring bimolecular collision theory approach, and both ΔH* and ΔS* were determined for forward and backward esterification reactions. The enthalpies of activation were 32.141 kJ/mol and 27.080 kJ/mol for the forward reaction and the backward reaction, and the entropies of activation were - 193.7 and -212.7 J/mol. K for the forward reaction and the backward reaction, respectively.
Nitrogen (N) is a key growth and yield-limiting factor in cultivated rice areas. This study has been conducted to evaluate the effects of different conditions of N application on rice yield and yield components (Shiroudi cultivar) in Babol (Mazandaran, Iran) during the 2015- 2016 season. A factorial experiment executed of a Randomized Complete Block Design (RCBD) used in three iterations. In the first factor, treatments were four N amounts (including 50, 90, 130, and 170 kg N ha-1), while in the second factor, the treatments consisted of four different fertilizer splitting methods, including T1:70 % at the basal stage + 30 % at the maximum tillering stage, T2:1/3 at the basal stage + 1/3 at the maximum ti
... Show MoreBackground: Dental casts come into direct contact with impression materials and other items that are contaminated by saliva and blood from a patient's mouth, leaving the casts susceptible to cross-contamination. The disinfectant solutions of the impression materials cause various adverse reactions. Therefore, disinfection of dental casts may be effective in preventing cross infection. This study was carried out to evaluate the surface hardness, dimensional accuracy, reproduction of details and surface porosity of type III, type IV and type IV extra hard dental stone after immersion in and spray by using SOLO and Sodium hypochlorite disinfectant solutions. Materials and methods: 240 Stone samples were prepared in rubber rings, A total of 60
... Show MoreThe issue, the existence of God Almighty, and the creativity of the universes including the whale, and assets and how diversified, and faith in him and his lordship and divinity, is a delicate issue, and very important and dangerous, and it occupied human thought old and new, and still occupy it until God takes the land and on it. Many complex issues of thought, behavior, and ethics have resulted in the belief of many communities in the existence of the Almighty, having ruled their minds, depicting their beliefs and distancing their thoughts about slippage and abuse. When they looked at the wonders of creatures and the minutes of the assets, they thought about the planetary and astronomical motion systems. His existence was denied by ath
... Show MoreYoung people represent the power and cornerstone of societies and their superiority is linked to their well-being. Their empowerment is as essential as the heart to the body, if it is corrupt, then the whole body is corrupt, and vice versa. The exposure to extremism and pressure from their families leads to violent acts and crimes for obtaining money through unknown organized bodies. This will drive them to fail in their life in an attempt to fulfill their most basic needs, which they have been deprived of by their families, the government, and other institutions. Therefore, governments should provide job opportunities for young people and provide entertainment centers, sports clubs, and family education centers that raise awareness of s
... Show MoreTourist business organizations face a challenging and the risks dynamic environment reflected its impact on the community and generate extra under pressure in the responsibilities and burdens of exceptional and affected much of factors, accidents and risks as a result of the actions and attitudes of disasters variety may exceed the geography of States border, which requires the absorption of risks facing the tourism and how to manage and deal with them scientific and reasonable grounds for the diagnosis and treatment of risk and how to reduce the aggravation and the different kinds.
As risks affecting the most important and vital to organizations as a tourist aspects of the market share and styles tourist
... Show MoreThe research tagged with (similar rulings in the holy heavenly books - the Holy Qur’an and the Bible) highlights that there are a number of rulings in the heavenly books that are similar to each other in terms of content, meaning and significance and did not change from one prophet to another because they relate to the basic interests on which social relations are built. Documenting ties, preserving rights, preventing abuse, etc. These are among the divine purposes in clarifying rulings in order to reach their goals and achieve their goals. Therefore, by combining these rulings, many problems and incidents that are the subject of disagreement and doubt between the two religions can be achieved and addressed. Those who want reform, righ
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