Propyl Formate Research Articles

Temperature Dependence of Ester Hydrolysis in Water.

The rate of the hydroxyl-promoted hydrolysis of ethyl acetate has been determined at every second degree between 4 and 50 o C in water an 50% (w/w) ethanol-water mixtures (10-40 o C). Similarly the rate of the proton-catalyzed hydrolysis of propyl formate has been determined in water at the same temperatures. It is found that the Arrhenius activation energy of the alkaline and acid hydrolysis shows an oscillatory dependence on themperature in water, but not in 50% (w/w) ethanol-water. The results are in accordance with previously reported finding of the acid hydrolysis of acetal in water and 55% (v/v) ethanol-water. The results are discussed in relation to proton-transfer reactions and recent relaxation data of water

Analysis of volumes of mixing for propyl and butyl formate withn-alkanes in terms of the Nitta model

The excess molar volumes of eight binary systems formed of propyl or butyl formate with four n-alkanes (from C6 to C9) have been determined at 25°C and atmospheric pressure. The data were obtained indirectly from densities measured experimentally with a vibrating-tube densimeter and then compared with those estimated using the Nitta model. This method yields good predictions of the symmetry of the v E curves given an average overall error for all the systems analyzed here smaller than 6 percent.

Non-aqueous polypyrrole colloids: Synthesis and characterization

The preparation of sterically-stabilized polypyrrole colloids via a dispersion polymerization route in non-aqueous media is described for the first time. Pyrrole polymerization was achieved using FeCl 3 as an oxidant/dopant in organic solvents such as methyl acetate, methyl formate and propyl formate. Macroscopic precipitation was prevented by the use of poly(vinyl acetate) as a polymeric surfactant. Various other surfactants were ineffective and consequently resulted in precipitation of polypyrrole. Several techniques were used for characterization of the dispersions including transmission and scanning electron microscopies (TEM and SEM), thermogravimetric analysis (TGA), charge velocity analysis and visible absorption spectroscopy. TEM indicated a polydisperse spherical morphology with a particle diameter in the range 100–300 nm. The compressed pellet conductivities of the dried dispersion were as high as 0.1 S/cm. These dispersions are often compared with bulk and colloidal polypyrrole prepared in aqueous media.

A study of the metastable dissociations of formate esters: a McLafferty rearrangement to a distonic radical cation

The metastable dissociations of formate ester radical cations were studied by using both threshold photoelectron photoion coincidence and tandem mass spectrometry. Kinetic energy releases for the unimolecular fragmentations were obtained from both mass analyzed ion kinetic energy (MIKE) and time-of-flight spectra. An important dissociation property of propyl formate radical cation is that the appearance energies of the three major fragment ions (C{sub 3}H{sub 6}{sup {sm bullet}+}, HC(OH){sub 2}{sup +}, and m/z 60 ({sup {sm bullet}}CH{sub 2}OCHOH{sup +} and C{sub 3}H{sub 7}OH{sup {sm bullet}+})) are the same as the ionization energy of the propyl formate molecule, resulting in the absence of a molecular ion in the braekdown graph. The three major fragment ions are all formed via rearrangement processes (stepwise McLafferty rearrangement) involving a common distonic intermediate. The rearrangements are exothermic and occur without an activation energy, a conclusion in agreement with that of Benoit, Harrison, and Lossing for the formation of HC(OH){sub 2}{sup +}. The heat of formation of the distonic intermediate formed by an {beta} hydrogen atom transfer was determined to be <579 kJ mol{sup {minus}1}. The rearrangement also pertains to butyl formate and may be a characteristic of the unimolecular dissociations of larger alkyl formate ester radical cationsmore » at low internal energies.« less

An electron spin resonance investigation of ester cation radicals at low temperatures. Proton transfer and rearrangement reactions

The cation radicals of a series of esters have been produced by γ-irradiation of CFCl3 matrices containing the ester at 77 K. In previous work cations of methyl and ethyl esters were investigated. In this work we report results for larger esters. The cations of these esters are found to undergo immediate internal proton-transfer reactions involving specific sites on one of the alkyl substituents. For example, deuteration studies show that proton transfer occurs from the terminal methyl group in propyl formate to produce —OCH2CH2CH·2, whereas in propyl acetate —OCH2ĊHCH3 is produced. The proton lost from these groups is assumed to add to an oxygen on the ester functional group. In the case of propyl acetate and esters with branched side chains we find that fragmentation reactions follow the proton transfer. In the cases of t-butyl acetate and isobutyl formate the fragmentation process occurs at 77 K and results in the isobutylene cation. Neopentyl formate gives evidence for the cation radical, an RCH·2 radical and the fragmentation radical cation as the sample is annealed. These results show that ester cation radicals are highly reactive even at low temperatures where proton-transfer and fragmentation reactions are found.

Liquid phase CO+H2 reactions in presence of ruthenium catalysts

Several effects on the hydrogenation of carbon monoxide in propanol in presence of ruthenium catalysts are examined. The homologation reaction is not observed, only propyl formate and propyl acetate are produced with any ruthenium catalyst. The pH-value is an important parameter: in acid media, the yield of propyl formate is noticeably increased indicating different catalytic active species. The addition of cesium salts is also benefitial for formate formation. This is not the case when water is associated with propanol as solvent. Finally, no ethylene glycol is detected. The process is found to be homogeneous and methanol seems to be the precursor of methyl formate.

Charge-exchange mass spectra of ethyl acetate, methyl proprionate and propyl formate

The absolute cross-sections, Q, for the charge exchange in the gas phase between twenty eight primary positive ions of known electron recombination energy, E, and three isomeric esters, ethyl acetate, methyl proprionate and propyl formate, have been measured. A plot of Q against E for a particular product ion constitutes a charge-exchange mass spectrum, c.e.m.s., from which the product ion's appearance potential is directly obtained. The appearance potentials of the three esters and eleven of their principle ionic fragments are reported.

Attraction of nematodes to metabolites of yeasts and fungi

The free-living nematodesPanagrellus redivivus andRhabditis oxycerca are strongly attracted to methyl, ethyl, propyl, butyl, and amyl acetate, to ethyl, propyl, and amyl formate and to ethyl propionate, but all the respective alcohols and acids are without effect. No loss of attraction is observed when the attractants are combined with lethal concentrations of the commercial nematicide sodium methyl dithiocarbamate.

Oil Saturation Measurements at Brown and East Voss Tannehill Fields

The partitioning tracer method was used to measure in-situ oil saturation in the Glorieta formation of the Brownfield and in the Tannehill sand of the East Voss Tannehill Unit. Such measurements are needed to evaluate the economic potential of applying an enhanced oil recovery process. Results obtained with this method also are presented. Introduction The amount of oil present in a reservoir is needed to evaluate applications of enhanced oil recovery processes. The residual oil saturation near the wellbore can be determined from cores and logs, but such data can be biase by abnormally high pressure drops and accompanying saturation changes. To measure in-situ oil saturation away from the wellbore, we employed the partitioning tracer method developed and licensed by Exxon Production Research Co. Measurements were made in the Glorieta (dolomite) formation of the Brown field and in the Tannehill sand of the East Voss Tannehill Unit. Tomich et al. and Bragg et al. have described the partitioning tracer method for measuring residual oil partitioning tracer method for measuring residual oil saturation and the theory behind it. In brief, the over-all procedure consists of three parts: (1) laboratory tests at procedure consists of three parts:laboratory tests at reservoir conditions to determine the chemical partitioning coefficients and rate of hydrolysis of the ester used,a mini-test to check the validity of the reaction-rate measurement and reservoir parameters, andthe main test to determine the oil saturation. The mini-test follows the same procedure as the main test. The oil saturation found with the mini-test can be the same as that of the main test. However, as the names imply, the volume of the reservoir contacted is different in each test. The mini-test may show that some change should be made in the test procedure and incorporated in the main test. Test Procedure The oil saturation measurement in the field requires the following sequence of steps.A slug of water is injected. The first portion of the slug contains both an ester (such as propyl formate) and methanol. The next portion contains only methanol. The selection of the ester depends on reservoir temperature.The slug is kept in the formation for a selected period of time to hydrolyze part of the propyl formate, period of time to hydrolyze part of the propyl formate, forming propanol and formic acid.The well is placed on production and samples of the produced water are analyzed for the tracer chemicals. produced water are analyzed for the tracer chemicals.Injection and production profiles are run several times during the test to determine where the fluids are entering and leaving the wellbore. Such information is necessary to define the reservoir model.The chemical concentrations measured for methanol, propyl formate, and propanol are plotted as a function of production. Then, these are compared with chemical concentration values generated by a computer model of the test application developed from pertinent reservoir and fluid parameters. The residual oil saturation is obtained by the best fit between computed and measured chemical concentration data determined by trial-and-error. Laboratory experiments using crude oil and brine samples (preferably from the test well) determine the partitioning coefficients of the propyl formate and partitioning coefficients of the propyl formate and propanol at reservoir temperature and pressure. propanol at reservoir temperature and pressure. JPT P. 17