Acid In Dodecane Research Articles

Mechanism of Acid-Catalyzed Decomposition of Dicumyl Peroxide in Dodecane: Intermediacy of Cumene Hydroperoxide

Acid-catalyzed decomposition of dicumyl peroxide in dodecane from 60 to 130 °C produces α-methylstyrene and phenol as the major products. Pseudo-first-order rate constants were determined as a function of the temperature for the reaction of DCP with dodecylbenzenesulfonic acid in dodecane and resulted in an Arrhenius plot exhibiting two distinct kinetic regimes with differing activation energies: 76.9 kJ/mol at low temperatures (measured from 60 to 90 °C) and 8.50 kJ/mol at higher temperatures (measured from 90 to 130 °C). With employment of a combination of kinetics, product analysis, and trapping experiments, evidence is presented to show the intermediacy of cumene hydroperoxide—a reactive intermediate absent from previous mechanistic descriptions of this process. The yield of cumene hydroperoxide production is discussed, and the mechanistic pathways for formation of the observed products are presented.

Effect of Aqueous Phase pH on the Dynamic Interfacial Tension of Acidic Crude Oils and Myristic Acid in Dodecane

The time dependence of the interfacial tension between water–acidic crude oil and water–synthetic oil was investigated for aqueous phase pHs ranging from 2 to 9 using the du Noüy ring method at 20°C. Myristic acid in dodecane was selected as a model (synthetic oil) for acidic crude oil containing indigenous surfactants, and the similarities and differences between the dynamic interfacial tension behaviours of the natural and synthetic crude oil systems were compared. The initial interfacial tension and the relaxation of the interfacial tension are sensitive to the aqueous phase pH for both systems. The adsorption kinetics of the indigenous surfactants and myristic acid could be well fitted with the monoexponential model, and the time constants obtained in this manner indicates that reorganization of the indigenous surfactants and myristic acid at the w/o interface are pH dependent. The experimental results also indicate that indigenous surfactants in acidic crude oil and myristic acid in dodecane have similar film formation behaviours at the w/o interface for the range of pHs investigated.

Mass-transfer in pertraction of butyric acid by phosphonium ionic liquids and dodecane

AbstractTransport of butyric acid (BA) through a supported liquid membrane (SLM) containing phosphonium ionic liquid (IL) Cyphos IL-104 and dodecane occurs by two mechanisms. The first is related to the physical solubility of undissociated acid in dodecane in the form of a monomer or dimer and the second to the reactive extraction of acid by IL. Although the model of pertraction indicates that increasing the mean concentration of acid in the feed, c F,lmv, increases the participation of pertraction based on the physical solubility; in the tested range of c F,lmv from 0 kmol m−3 to 0.45 kmol m−3 it does not play an important role and at the highest c F,lmv value, less than 10 % of the overall BA transport were achieved. The presence of IL in SLM considerably increases the value of the overall mass transfer coefficient in pertraction at low BA concentrations. However, at c F,lmv > 0.4 kmol m−3 its values are similar for SLMs with and without IL. Compared to lactic acid, the pertraction of BA through the same SLM is about five times faster. Reactive transport of BA is connected with the back transport of water via reverse micelles decomposition and formation on the extraction and stripping interfaces.

Diesel-like Hydrocarbons from Catalytic Deoxygenation of Stearic Acid over Supported Pd Nanoparticles on SBA-15 Catalysts

Palladium catalysts with different loading on SBA-15 have been prepared using a direct synthesis method and characterized with X-ray diffraction, micrograph images, and X-ray photoelectron spectroscopy. Mesoporous Pd-SBA-15 was an active and selective catalyst for deoxygenation of stearic acid in dodecane as a solvent at 300 °C under 17 bar of 5 vol% H2 in argon as a carrier gas in a semibatch reactor. Palladium/SBA-15 catalysts have been prepared using a direct synthesis method and characterized with X-ray diffraction, micrograph images, and X-ray photoelectron spectroscopy. They were an active and selective catalyst for deoxygenation of stearic acid in dodecane as a solvent at 300 °C under 17 bar of 5 vol% H2 in argon as a carrier gas in a semibatch reactor.

Synthesis of Biodiesel via Deoxygenation of Stearic Acid over Supported Pd/C Catalyst

High catalytic activity was achieved in the deoxygenation of stearic acid in dodecane in a temperature range of 270–300 °C under 17 bar helium over palladium on nanocomposite carbon Sibunit. Besides n-heptadecane, which was obtained previously in this reaction with palladium on activated carbon, n-pentadecane was also formed in significant amounts.

Neutron spin echo study of low-Tc ferrofluid

We studied the diffusion of single domain particles of Mn0.3Zn0.7(Fe2O4) (Rp≈100Å) stabilized by oleic acid in dodecane near the transition temperature Tc of particles from superparamagnetic to paramagnetic state. The structure of the ferrofluid has been studied by small angle neutron scattering. We found a strong density fluctuation near Tc≈20°C and H=0, induced by critical spin diffusion. In addition, we studied this system using neutron spin echo (NSE) inelastic scattering. The temperature variation of the self-correlation function GS(T,q,t)=exp[−q2D(t/τ)β(T)] at momentum transfer q=0.07Å−1 in the time interval t=0.5–40ns reveals strong influence of magnetic fluctuations on the mobility: these fluctuations decrease the diffusion rate D and induce stretched relaxation (β≈0.6) at T<Tc≈16°C. Above Tc, Stokes diffusion dominates (β≈1)

Distribution Study of the Hydration of Nitric Acid in Dodecane

The hydration of nitric acid in dodecane was determined on the basis of the acid and water distribution between aqueous acid solutions and dodecane at 298 K. By analyzing the distribution data, mono- and decahydrate of nitric acid in addition to the anhydrous acid were found in dodecane. The solvent influence on the formation of the acid hydrates in dodecane was also compared with the results obtained in benzene.

Analytical utility of coupled transport across a supported liquid membrane: Selective preconcentration of zinc

A liquid membrane comprising 5–10% bis(2,4,4-trimethylpentyl)phosphinic acid in dodecane that is supported between an aqueous sample at pH 4.7–6.0 and a 0.1 M HCl receiver results in uphill transport of Zn(II) from the sample into the receiver. With 2 ml of receiver, a 5 cm 2 membrane and 60 min dialysis time, Zn(II) is preconcentrated by a factor of ca. 13 when the initial concentration in the sample is in the range 1.5 × 10 −7−1.5 × 10 −4 M. The enrichment factor is directly proportional to time up to 30 min since the transport rate of Zn(II) across the membrane is constant over this period. At longer times the flux is slowed as the system begins to approach equilibrium. The presence of other metals such as Cu(II), Co(II), Ni(II), Cd(II), Pb(II) and Fe(II) does not change the enrichment factor for Zn(II), even when the interferent is at a concentration high enough for the rate of transport (nmole/min) of the interferent and Zn(II) to be about the same. The flux of Zn(II) was about 40 times that of Cu(II) and 100 times that of Co(II) when their concentrations in the sample were equal. The other metal ions examined are not significantly transported.

Structure in dispersions of polymer particles

AbstractIn concentrated polymer latex systems where strong repulsive forces, either electrostatic or steric, exist between the particles ordering of the particles occurs. The structure formed can be examined by small angle neutron scattering and experiments indicate that the arrangement of the particles is liquid‐like. Results are reported for a poly(‐styrene) latex in an aqueous electrolyte solution and for a poly(‐deuteromethyl methacrylate) latex, with the particles stabilised by poly‐12‐hydroxy stearic acid in dodecane.

Extraction of zirconium from nitric acid media by butyl lauryl phosphoric acid in dodecane

Butyl lauryl phosphoric acid (HBLP) was chosen as a model compound of secondary degradation products of Purex process solvent. The extent of zirconium complexation by this compound is similar to that of dibutyl phosphoric acid or bis(2 ethyl hexyl) phosphoric acid. The mechanism of zirconium extraction by HBLP was studied. The nature of the extracted species could not be unambiguously established. Tributyl phosphate has an antagonistic effect on the zirconium extraction by HBLP. Removal of HBLP from the solvent cannot be accomplished by alkaline washes representative of solvent clean-up procedures used in the Purex process. This could lead to a long term build-up of this type of compound under Purex processing conditions. The threshold HBLP concentration for an enhancement of zirconium extraction is 2 × 10 −4 M.

Radiochemical Separations by Liquid-Liquid Chromatography Using PSM Support

Radiochemical separations of metal lons by liquid-liquid chromatography were carried out on 2-cm long minicolumns packed with 4 to 6 ..mu..m porous silica microspheres containing 25 to 30 weight percent of 1.5 F di(2-ethylhexyl) phosphoric acid in dodecane. Column performance was evaluated using the elution of both tracer and macro quantities of Eu(III). Plate heights for tracer scale elutions were 0.015 to 0.025 mm and 0.05 to 0.07 mm at v = 2 and 30 cm/min, respectively. The separation of certain dipositive metal ions, tripositive lanthanide lons, and tripositive transplutonium lons were studied using the high efficiency minicolumns.