Fabio Faraguna

Modeling of dibenzothiophene oxidative desulfurization using response surface methodology

ABSTRACT The effect of reaction temperature, mixing speed and oxidant to catalyst volume ratio, including their interactions on the oxidative desulfurization of dibenzothiophene by using response surface methodology was studied. Hydrogen peroxide was used as oxidant and acetic acid as catalyst. The obtained model accurately predicts conversion of dibenzothiophene and the best conversion of 98.7% was observed at temperature 70°C, mixing speed of 1250 rpm and oxidant to catalyst volume ratio of 1:1. At high temperatures, a major limitation of the desulfurization process is the mass transfer and the high mixing speed is needed to achieve an efficient process.

Crystallization and Pour Point of Solutions of the Dispersant Poly(Styrene-Co-Methacrylate) Viscosity Modifiers in Lubricating Base Oil

ABSTRACT Dispersant viscosity index improvers were synthesized by free radical copolymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA), dodecyl methacrylate, octadecyl methacrylate, and styrene in solution of mineral base oil. Studies included the dependence of the pour point and low-temperature crystallization behavior (characteristic temperatures and enthalpies) of the solutions of these polymer viscosity modifiers (VMs) on the amount of dispersant comonomer, DMAEMA, in the copolymer, weight average molecular weight of the copolymer, and concentration of the polymer in oil. Incorporation of dispersant comonomer in poly(styrene-alkyl methacrylate) structure additionally decreases the pour point of its solutions even for a very small concentration: the pour point of the base oil reduces from −9 to −25°C and −33°C for the 0.1 and 0.5 wt% concentrations of polymer, respectively. For concentrated 50 wt% solutions the enthalpy of crystallization decreases linearly with a decrease in the long-chain alkyl methacrylate share in copolymer. There is no unambiguous correlation between the pour point and crystallization parameters of semidiluted and diluted polymer solutions obtained by differential scanning calorimetry.

Novi petrokemijski procesi na temelju izravne pretvorbe metana

Petrokemija je grana kemije i kemijskog inženjerstva koja proucava reakcije i procese dobivanja i svojstva proizvoda iz naftnih prerađevina i prirodnoga plina, a koji ne služe kao goriva ili maziva. U svojim pocetcima petrokemija, odnosno organska kemijska industrija, temeljila se na etinu i Reppeovim sintezama. Danas su osnovne petrokemikalije olefini i aromatski ugljikovodici, s težnjom razvoja novih procesa i sve vece uporabe sinteznog plina, metana i drugih alkana kao ishodnih sirovinskih komponenti. U ovom radu dan je pregled reakcija i novih procesa izravne pretvorbe metana u vrjednije petrokemijske proizvode. Kroz pojedina poglavlja u radu su detaljnije opisane reakcije parcijalne oksidacije metana, dehidroaromatizacije metana te oksidacijskog i neoksidacijskog spajanja metana u vise ugljikovodike.