Abstract. Fatty acid deoxygenation is a method for producing renewable hydrocarbon fuels such as green diesel, jet biofuel and biogasoline. In the present commercial method, deoxygenation is directly applied to vegetable oils through liquid phase hydrotreatment. This method is expensive because it consumes a large amount of hydrogen and requires severe operating conditions. The objective of this study was the production of a diesel-like hydrocarbon fuel that can be considered as drop-in replacement for petroleum-based diesel fuels, by catalytic thermal decarboxylation of Mg-Zn basic soap. In particular, this study investigated the decarboxylation of Mg-Zn basic soap at low temperature and pressure, without external supply of hydrogen. The Mg-Zn basic soap (9/1 mole ratio of Mg/Zn) was derived from palm stearin and decarboxylated at 350 °C and atmospheric pressure for 5 hours. The basic soap effectively decarboxylated, yielding a diesel-like hydrocarbon fuel with a liquid product yield of 62%-weight. The resulting hydrocarbon product is a complex mixture consisting of normal paraffins in the range of carbon chain length C 8 -C 19 , iso-paraffins and various olefin products.

Production of sustainable diesel was conducted via hydrogen-free decarboxylation of palm stearin basic soaps. Metal soaps are alkaline earth and transition-metal salts combined with carboxylic acids with 7−22 carbon atoms. Stearin basic soaps were prepared by direct reaction of palm stearin and mixed metal (Ca, Mg, and Zn) hydroxides. The stearin basic soaps were decarboxylated at 370 °C for 5 h to produce liquid crude bio-hydrocarbon, also known as sustainable diesel. The stearin basic soaps were characterized by Fourier transform infrared (FTIR) and thermogravimetric analysis, and the resulted liquid bio-hydrocarbons were analyzed by GC equipped with a flame ion detector. The hydroxyl band at 3678 cm −1 observed from FTIR spectroscopy indicated that the Ca/Mg/Zn ions were associated with the −OH ions in the compounds. This proved that the soaps produced from this work were basic metal soaps. The thermal stability of the soaps was examined up to 1000 °C, and the decomposition of stearin basic soaps was observed in the range of 300−500 °C. The metal contained in the basic soaps affected their thermal characteristics. Liquid crude bio-hydrocarbon with carbon chain length between 8 and 20 has been obtained from decarboxylation of stearin basic soaps. In this study, the decarboxylation of stearin basic soaps resulted in sustainable diesel as the main product. This promising process is expected to open a plethora of opportunities in the production of sustainable diesel.

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The basic metal soap from oleic acid submitted to pyrolysis to produce gasoline-like hydrocarbon fuels (biogasoline). The pyrolysis was carried out in a semi-batch reactor at 450°C and a feeding rate of 5 g/15 min. The influences of various metal (Ca, Mg, Zn) hydroxides, which are used to made basic soap, have been examined. The bio hydrocarbon of basic metal soap was characterized by GC-FID and FT-IR, showing the formation of paraffin, iso-paraffin, olefin, ketone, and aromatics. The liquid fraction derived from the pyrolysis of basic metal soap was dominated by gasoline (C7-C11) fraction hydrocarbon. The maximum yield of light C7-C11 hydrocarbon was 82.3 %-mol fraction of basic Ca soap and the highest yield of biohydrocarbon reached 34.77 wt.% from pyrolysis of basic Mg soap.

Catalytic thermal decarboxylation of basic soaps derived from palm kernel oil to produce dropin fuel was investigated. The C12/14 and C12/16 methyl ester had been used as the model compounds of this study. The purpose of this study was to produce drop-in fuel, especially jets biofuel, by catalytic thermal decarboxylation of basic soaps from palm kernel oils. In this study, two types of Magnesium-Zinc metal combination were used for preparing the basic soaps, both directly have a role as a catalyst. The reaction was carried out at 370°C and atmospheric pressure for 3 hours in the semi-batch reactor. Approximately 41 and 43 weight% of the yield and selectivity of about 97 and 98% toward the jets biofuel had been obtained in both experiments, respectively. The results showed that decarboxylation of basic soaps of C12/14 and C12/16 methyl ester were converted into drop-in fuel, especially jets biofuel in the relatively good yield of conversion.