Oleik-asit-füzel yağı fraksiyonu esterleşme ürününün yağlama yağı olarak değerlendirilmesi

Özgülsün, Aykut
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Fen Bilimleri Enstitüsü
Yağlama yağlan günlük yaşamda çok çeşitli kullanım alam ile, taşıt yağlama yağlan ve endüstriyel yağlama yağlan uygulamalarında karşımıza çıkar. Yağlama yağlan petrol kökenli (sıvı hidrokarbon yağlan-madeni yağlar) ve petrol dışı kökenli (sentetik yağlama yağlan) olabilir. Sentetik yağlama yağlan içinde ise, yağ asidi esterlerinin önemli bir konumu vardır. Yağ asidi esterleri, yenilenebilir kaynaklara dayalı, çevre dostu yağlama yağı seçenekleri arayışları içinde de ayrı bir öneme sahiptir ve mevcut petrol kökenli yağlama yağlarının pekçok alanda isteklere yanıt verememesi nedeni ile de bu önem sürekli artmaktadır. Bu çalışmada oleik asit ile tüzel yağı fraksiyonu esterleşme ürünü sentetik yağlama yağı adayı olarak sunulmaktadır. Deneysel çalışmada esterleşme tepkimesi incelenerek ester ürünün standart yağlama yağı özellikleri belirlenmiştir.
Basic oleochemicals are derived principally from natural feedstoks and are referred to as natural oleochemicals. Oleochemicals produced from petrochemicals are classified as synthetic oleochemicals. Raw materials for most natural oleochemicals are tallow, vegetable oils and tall oil. Basic oleochemicals are produced from the triglycerides in tallow and vegetable oils by hydrolysis (fat splitting) or methylation (methylester formation). Oleochemical products may be classified as fatty acids, fatty alcohols and glycerine. Natural glycerine is a by product of the oleochemical processes-saponification, hydrolysis and methylation. Fatty alcohols are derived from natural sources via methyl esters and fatty amines via fatty acids. The end-use markets for basic oleochemicals are extensive, for either the direct uses of fatty acids, methly esters and glycerine or for the intermediate uses of their derivatives. Fatty acids primarily are obtained directly from animal or vegetable sources resulting in linear even-numbered carbon chains. The initial process for obtaining fatty acids from fats and oils is hydrolysis. It is possible to produce various industrial products from fatty acids. Among the fatty acid products fatty acid esters have significant positions. General uses of fatty acid esters:. Solvents,. Plasticizers,. Resins,. Plastics,. Coatings,. Perfumes,. Flavors,. Cosmetics,. Soap, x . Medicinals,. Lubricants and. Biofuels. Esters are known as natural lubricating oils. Besides being used as lubricants like other esters type (diesters, trimelliate esters, C36 dimer acid esters, phthalate esters and polyols), they can also be evaluated as synthetic lubricating oils. Prior to the early 19th century the main lubricants were natural esters contained in animal fats or in vegetable oils. During World War II a range of synthetic lubricating oil was developed. Today, synthetic lubricating oil technology of high quality is achieved. A wide variety of raw materials can be used for the preparation of ester type base fluids and this can affect a number of lubricant properties including:. viscosity,. flow properties,. lubricity,. thermal stability,. hydrolytic stability,. solvency and. biodegradability. Today synthetic lubricating oils are based on renewable sources excluding petroleum and they are very significant in researches about enviromentally acceptable lubricating oil alternatives. This significance has been increased continously since the present petroleum based lubricating oils are not able to satisfy the needs in various areas. An environmentally acceptable lubricating product could be defined as a material which when used would maximize protection or rninimize pollution of air, water, soil and sediments. At the same time it should minimize health and safety hazards to humans, aminals and plants during the process of production, use or accidental misuse, disposal or recycling. There are three categories for environmentally acceptable lubricating products: primary, secondary and tertiary. Tertiary products are produced from recycled components. Examples are rerefined motor oils. Secondary products are those which help minimize the pollution generated by machinery and vehicles. They are really variations of conventional products. Examples of secondary products are energy- conserving motor oils, fill-for-life lubricants, fuel-economy lubricants, and emissions-friendly diesel oil formulations. The last category of environmentally acceptable products is primary products. This category of products offers the greatest challenge technically. These nontoxic and biodegradable products should cause little if any harm when released into the environment. Environmentally acceptable XI lubricants fit into this category with examples being vegetable-oil-based lubricants and water-based metal-working fluids. Using vegetable oil based product for environmentally acceptable lubricants has many advantages. It is nontoxic, it is biodegradable, it is a renewable resource, and, it has a reasonable cost when compared to synthetic fluids. Oleic acid (cis-9-octadecenoic acid, CH3(CH2)7CH:CH(CH2)7COOH) is one of the most important fatty acid. Oleic acid is generally considered to be the predominant fatty acid in nature. It comprises 50% or more of the total acids of many fats; few fats are known to contain less than 10% of this acid. The esters of oleic acid can be used as a lubricating oil. In this study, the esterification product of oleic acid with fraction of molasses fusel oil as lubricating oil candidate is investigated. The experimental work covers the steps cited below: 1. The characterization of the fusel oil fraction and oleic acid 2. The determination of the optimum conditions for the esterification reaction 3. The refinement of ester product 4. The determination of the lubricating properties of ester product. Molasses fusel oil is a by product of the fermentation process of the industrial ethanol production. It is an alcohol mixture having a boiling range of 80-132°C. Fusel oil used in experiments was obtained from Turkish Sugar Factories Inc. It had a high (8.6% v/v) water content, and its density at 20°C was 853.6 kg/m3. Because of high water content of fusel oil as a reactant, the compliteness of reaction will be affected negatively. Therefore, fusel oil was distilled, and the higher boiling fraction (above 120°C and 75 v/v of fusel oil) of fusel oil containing 0.1% (v/v) water was used as the esterification reactant in the experiments. The composition of fusel oil fraction according to the results of the gas-liquid chromatography analysis is showed below: wt% The oleic acid was obtained from KAYKE Chemicals Inc. The technological characteristics of the oleic acid were determined according to the standart methods of oil and fat analysis. The composition of oleic acid was subjected to capillary gas chromatographic analysis with the apparatus of Hewlett Packard 5890 series II fitted with a flame ionization detector (FED). The technological characteristics of the oleic acid are shown in Table 1. XII Table 1. The technological characteristics of oleic acid. The reaction performed in a three-necked flask equipped with a reflux condenser, contact thermometer and a thermometer. Rection temperatures were held constant within a range of ± 1°C and the neck for thermometer was used for taking samples from the reaction mixtures for chromatographic analysis at certain time intervals. Reaction mixtures were heated on a magnetic heater and stirrer to experiment temperature, catalyst and desiccant were added to the mixture at that moment. The samples were analyzed with Iatroscan TH-10 MK IV (TLC/FID). One ml samples for TLC/HD analysis were taken from the reaction mixtures at certain time intervals and then they were quenched in test tubes and all the test tubes were settled down in a vessel filled with ice to stop the reaction. The variables affecting the ester yield during esterification reaction such as reaction temperature, the molar ratio of acid/alcohol, type and amount of the catalyst used and duration were investigated as the next step in the experimental work. Sulphuric acid was chosen as catalyst. To remove of water silica gel was chosen instead of magnesium sulfate and benzene. The beginning reaction conditions were chosen as follows: Acid/Alcohol molar ratio: 1/1 (Stoichiometric molar ratio); Temperature : 1 10±1°C (The temperutare at which the alcohol well boiled and condensed); Catalyst: 1% H2SO4 by the weight of acid. xni Effect of the Temperature The reactions were carried out with the aim of observing the effects of temperature decrease on the ester yield and the temperatures were chosen less than 1 10°C namely 100°C, 90°C, 80°C and 70°C aiming a reduction in the energy necessity. A comparison between the ester yields at these temperatures after 60 and 90 minutes are showed below: It is observed that ester yield was positively affected by the increase in temperature. The ester conversions in the reactions conducted at 1 10°C, 100°C and 90°C after 90 minutes are nearly equal. Hence, 90°C was found to be the most suitable reaction temperature because of the ester conversion and comsumption of energy. Effect of the Molar Ratio Among the variables affecting the ester yield in the esterification reaction, the most important one is the molar ratio of the reactants. Since the reaction is reversibl, an increase in the amount of one of the reactants will result in higher ester yields. To determine the effect of molar ratio, oleic acid was esterified at 1/2, 1/3 and 2/1 oleic acid/fusel oil fraction molar ratios using 1% H2SO4 by weight of oleic acid as catalyst and keeping the reaction temperature at 90±1°C. As expected a higher yield of ester was obtained in a shorter period of time for 1/2 and 1/3 molar ratios compared to 1/1. The yield obtained in the reaction with the molar ratio of 2/1 was 56.6% after 120 minutes while an ester yield of 98.5% was observed in the reaction with 1/2 molar ratio in the same period. After 30 minutes the ester yields are nearly the same at 1/2 and 1/3 molar ratios. Hence 1/2 found to be the most suitable molar ratio of oleic acid/fusel oil fraction. Effect of the Type and Amount of Catalyst In experiments, in which the effect of the variation in the catalyst amount was investigated, the reaction conditions were as follows: Temperature : 90±1°C; Acid/Alcohol molar ratio : 1/2; Catalyst: 0.5%, 0.75%, 1.25% and 1.50% of H2S04 by the weight of the acid. As the amount of the catalyst was increased from 0.5% to 1.5% the yield increase was occured in a shorter of time. A comparison between the ester yields at every amount of catalyst after 60 and 120 minutes are showed below: xiv 1.25% by the weight of acid was found to be the appropriate amount for the reaction. After 60 minutes the ester yield at 1.25% by the weight of the acid was observed 97.3%. Hence the reaciton duration was chosen 60 minutes. Changing the catalyst from 1.25% H2SO4 to 1.25% p-toluene sulfonic acid proved that H2SO4 was superior under the applied conditions. After all the experiments realized between oleic acid and fusel oil fraction, optimum reaction conditions were chosen as follows: the Duration Temperature Acid/Alcohol molar ratio Type of catalyst Amount of catalyst 1 hour 90±1°C 1/2 H2SO4 1.25 % by the weight of the acid In the refinement step of the esterification reaction, the mixture which composed of ester product, oleic acid, fusel oil fraction, sulphuric acid and desiccant were first allowed to cool to room temperature. The mixture was filtred to remove the desiccant from the mixture product. Excess fusel oil fraction in the mixture was removed in a rotary evaporator under reduced pressure. The mixture was washed many times with distilled water (30°C) to remove the catalyst from the mixture. The ester was dried over anhydrous sodium sulfate. The refinement steps of the mixture of esterification product are shown in Figure 1. The properties of the lubricating oil were determined according to the ASTM standart tests. The results are shown in Table 2. Oleic acid-fusel oil fraction esterification product was presented as environmentally acceptable lubricating oil or lubricating oil additive. Table 2. The properties of the esterification product. XV Mixture of Esterification Product Cooling to room temperature Filtration Desiccant Evaporation (Silica gel) -» Fusel oil fraction Washing with distilled water at 30°C Sulphuric acid Drying over sodium sulfate at 120°C Ester Product Figure 1. The refinement steps of esterification mixture. Table 2. The properties of the esterification product.
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1997
Anahtar kelimeler
Endüstriyel yağlar, Esterleşme, Oleik asit, Yağlama, Industrial oils, Esterification, Oleic acid, Lubrication