Nitrasi metil risinoleat menggunakan pereaksi campuran asam nitrat dan anhidrida asetat telah dilakukan. Nitrasi dilakukan dengan cara memvariasi konsentrasi metil risinoleat dan temperatur reaksi dalam rangka mengetahui laju reaksi (r), orde reaksi (n), konstanta laju reaksi (k), energi aktivasi (Ea), faktor frekuensi Arhenius (f) dan waktu reaksi optimum. Hasil nitrasi metil risinoleat kemudian ditentukan densitas, viskositas, indek bias, bilangan iod, kelarutan dalam solar serta penentuan struktur molekul hasil nitrasi metil risinoleat menggunakan instrumen Fourier Transform Infra Red (FTIR) spektrometer dan Gas Cromatography-Mass Spectrometer (GC-MS). Karakterisasi terhadap minyak solar setelah diberi tambahan zat aditif juga dilakukan dengan menentukan berat jenis, viskositas, titik tuang, titik kilat, Conradson Carbon Residue (CCR), panas pembakaran, dan penentuan indek setana. Hasil penelitian menunjukkan bahwa nitrasi metil risinoleat (0,018 mol) menggunakan pereaksi campuran asam nitrat (0,027 mol) dan anhidrida asetat (0,027 mol) pada temperatur 29 oC selama 90 menit, menghasilkan metil risinoleat nitrat sebanyak 38,8%. Laju nitrasi metil risinoleat dengan konsentrasi awal sebesar 0,375; 0,319 dan 0,261 M secara berturut-turut adalah 3,73 x 10-5; 3,00 x 10-5 dan 2,69 x 10-5 M/detik. Reaksi nitrasi metil risinoleat menggunakan pereaksi campuran dengan konsentrasi berlebih merupakan reaksi orde 1 semu dengan konstanta laju pada temperatur 29 oC adalah 8,67 x 10-5 detik-1. Energi aktivasi (Ea) dan faktor frekuensi Arhenius (f) masing-masing adalah 49,77 kJ/mol dan 5,51 x 104 detik-1. Produk hasil nitrasi metil risinoleat memiliki densitas 0,9678 (g/mL), viskositas 32,43 (cPs), indek bias 1,4604, bilangan iod 25,8 dan larut dalam solar secara sempurna. Penambahan zat aditif (sampel A) sebanyak 0,5% (v/v), tidak menyebabkan solar ke luar dari standar spesifikasinya dan meningkatkan indek setana dari 51 menjadi 54. Dengan demikian produk hasil nitrasi metil risinoleat dapat digunakan sebagai zat aditif dalam meningkatkan angka setana.

Nitration of methyl ricinoleate using the mixture of nitric acid and acetic anhydride has carried out. Methyl ricinoleate nitration was done by varying concentration of methyl ricinoleate and reaction temperature in order to determine the reaction rate (r), order of reaction (n), the reaction rate constant (k), activation energy (Ea), Arhenius frequency factor (f) and the optimum reaction time. The product of the nitration of methyl ricinoleate was then characterized to determine the value of density, viscosity, refractive index, iodine number, solubility in diesel and molecular structure of methyl ricinoleate nitration results using instrument of Fourier Transform Infra Red (FTIR) spectrophotometer and Gas Cromatography-Mass Spectrometer (GC-MS). The characterization of diesel oil after the addition of additive was conducted by determination of specific gravity, viscosity, pour point, flash point, Conradson Carbon Residue (CCR), heat of combustion, and Calculated Cetane Index (CCI) determination. The results showed that the nitration of methyl ricinoleate (0.018 mole) using reagent the mixture nitric acid (0.027 mole) and acetic anhydride (0.027 mole) at a temperature of 29 °C for 90 minutes, producing methyl ricinoleate nitrate of 38%. The nitration rate of methyl ricinoleate with initial methyl ricinoleate concentration of 0.375, 0.319 and 0.261 M was 3.73 x 10-5, 3.00 x 10-5 and 2.69 x 10-5 M sec-1 respectively. The nitration was performed with the excess concentration nitric acid was pseudo first order reaction, with rate constant at 29 oC was 8.67 x 10-5 sec-1. The activation energy (Ea) and frequency factor (f) were 49.77 kJ/mol and 5.51 x 104 sec-1 respectively. The products (sample A) has a density of 0.9678 (g/mL), viscosity 32.43 (cPs), refractive index 1.4604, iodine number 25.8 and completely miscible with diesel fuel. Addition of 0.5% (v/v) the additive (sample A), did not cause the diesel fuel out from diesel fuel specifications and able to increases cetane index of 51 to 54. Therefore, the products of the nitration of methyl ricinoleate can be used as additives for improving of cetane number.

Kata Kunci : nitrasi, metil risinoleat, metil risinoleat nitrat, zat aditif, indek setana