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Industrial production of mixed tertiary ethers by reacting methanol or ethanol with a mixed tertiary olefin stream is a distinct possibility. Consequently, the synthesis of mixed ethyl tertiary alkyl ethers from ethanol and mixtures of reactive iso-olefins in an isothermal integral packedbed reactor is studied. The rate expressions in terms of activities for the individual reaction rates in this family of ethers are taken from related work. These kinetic expressions are utilized here for comparison with experimental data obtained in a packed-bed reactor containing Amberlyst 15 ion-exchange resin catalyst for a mixed iso-C 6 olefin feed stream as well as for a mixed C 4 , C 5 , and C 6 iso-olefin stream. Etherification and isomerization conversions increase with space time at the lower temperatures; however, at the higher temperatures equilibrium limitations are approached. As a function of temperature, the conversions first increase and then decline due to thermodynamic limitations for these exothermic reactions. Good agreement is obtained between predictions and experiments.

Abstract. Magnesium silicate with various silica and magnesium oxide ratios (SiO 2 /MgO ratios) was used as the adsorbent for a study of adsorption of free fatty acid (FFA) in crude palm oil (CPO). Magnesium silicate was prepared from magnesium nitrate or magnesium sulfate solution precipitated with a solution of sodium silicate derived from rice husk. SiO 2 /MgO ratios of the magnesium silicate synthesized from magnesium nitrate and magnesium sulfate were 3.93, 3.75, 2.74, 2.40, 1.99 and 3.96, 3.61, 3.51, 2.91, 2.69, respectively. FFA adsorption on the magnesium silicate was carried out by adding 1 gram of the adsorbent to 50 grams of CPO and shaking for 1 hour at 50 o C. It was found that SiO 2 /MgO prepared from magnesium nitrate ratio of 1.99 had the highest adsorption capacities of 185 mg of FFA per gram of adsorbent. In addition, increasing of SiO 2 /MgO ratios of magnesium silicate was found to reduce the adsorption capacities due to decreasing of FFA chemisorption. The effect of dosage amount to equilibrium adsorption capacities were carried out by adding different amount of magnesium silicate (SiO 2 /MgO ratio of 1.99) to 50 grams of CPO. The result showed that efficiency decreased when dosage increased. The Fruendlich and Langmuir isotherm were applied to describe this absorption system. The values of maximum sorption capacity (Q 0 ) and Langmuir's sorption affinity (b) in the Langmuir equation obtained by linear-regression were minus values which were physically meaningless. Thus, FFA adsorption on magnesium silicate was both physisorption and chemisorption and well represented by the Fruenlich isotherm.

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