Papers by Keyword: Ester

Abstract: Density and viscosity are two major rheological properties that determine the performance of an isopropyl laurate (IPL) ester based drilling fluid. In this study, the effect of barite particle size on the IPL drilling fluid system settling behaviour was investigated using five particle sizes namely-32, 32-45, 45-75, +75μm and the unsieved barite. Stokes’ law of separation theory was employed in the analysis. It was found that smaller barite particle sizes (<75μm) enhances the settling resistance. An ideal barite particle size of-32μm was chosen and used in the subsequent formulations to obtain optimum rheological properties by varying the amount of viscosifier used at 4.0, 10.0 and 20.0g marked as sample (a), (b) and (c). These samples were analysed for their rheology by using the conventional Fann viscometer calibrated using Bingham model. The results showed that sample (b) exhibited the most promising performance based on the plastic viscosity, yield point and gel strength rheological analyses. Moreover, IPL drilling fluid sample (b) showed improve particle suspension ability for more than 78 hours when compared to IPL drilling fluid system prepared using unsieved barite particles. The results suggested that palm oil based isopropyl laurate ester has the potential to be used as based fluid in the ester based drilling fluid system.

Abstract: A quantitative structure–property relationship (QSPR) model for predicting the standard net heat of combustion () was developed based on the ant colony optimization (ACO) method coupled with the partial least square (PLS) for variable selection. Five molecular descriptors were screened out as the parameters of the model, which were finally constructed using multi-linear regression (MLR) method. A reliable model of five parameters for predicting the of esters was established, which can provide some help for engineering to predict the based on only their molecular structures.

Abstract: Polystyrene beads modified with ester group for the separation of n-heptane/toluene have been successfully prepared. The synthesized beads were characterized by fourier transform infrared spectroscopy and thermogravimetric analysis. The effects of ester group on equillibrium swelling ratio and toluene selectivity were studied. The selective factor firstly increases then decreases with the increasing of ester group content. When the content of ester group is 30%, selective factor reaches maximum, the value is 1.62. Polystyrene beads modified with ester group show excellent thermal stability.

Abstract: A novel and efficient method for the synthesis of 4-hydroxy-6-substituted-pyrazolo [3,4-d] primidines with acetic acid via phenol esters intermediate has been developed. Compared to the results obtained from the base substituted conditions, acetic acid catalyzed synthesis afforded target products in good yields.

Abstract: Using methoxy polyethylene glycol methacrylate (MPEGMA), butyl acrylate (BA), Methyl allyl sulfonate (SMAS) as the raw materials, we can compose them to multipolymer in redox system. Through analyzing the factors and adjustment of orthogonal experimental results, the optimum technology of synthesis are shown as follows: n(MPEGMA):n(BA):n(SMAS)=5:12:2, n(H2O2)/n(Vc)=6, and the reaction temperature is 30°C. When the volume of superplasticizer is 0.42%, water cement ratio is 0.3; the initial fluidity of cement paste can get to 238mm, and within 1 hour without any loss.

Abstract: With gallic acid and n-butanol as main materials, a new dendrimer micromolecular compound with the skeleton of gallic acid was synthesized by reactions of esterification and etherification of gallic acid. The structure of product was detected by elemental analysis, ¹H NMR, IR and MS. The target molecule has the structure of alkyl ester and phenoether. The differential scanning calorimeter (DSC) and polarizing optical microscope (POM) measurements showed the target molecular behavior of mesophase and its streak textures belong to nematic. Its temperature range of mesophase was 78 °C during heating process and 58 °C during cooling process. The results showed that dendrimer molecule can formed with the structural unit of gallic acid and it has lower melting point and behaviors of thermotropic liquid crystal.

Abstract: Benzyl 4-ethyloctanoate was synthesized by the reaction of 4-ethyloctanoyl chloride with benzyl alcohol, and its synthesis conditions were optimized. The yield of benzyl 4-ethyloctanoate was about 93%. Based on the synthesis of benzyl 4-ethyloctanoate, phenethyl 4-ethyloctanoate, phenylpropanol 4-ethyloctanoate and cinnamyl 4-ethyloctanoate were prepared. The odor evaluations indicate that these four new ester compounds have floral and sweet note. These ester compounds have relatively high molecular weights and can be used as fixing agent to prolong the fragrance compounds lifetime.

Abstract: A novel kind of ester has been synthesized as the ligand to prepare the PbS nanocrystals (NCs). When Pb(acac)2 (lead acetylacetonate) was used as the lead source, the (200) crystal plane of the ester capped PbS NCs became preponderant during the coarsening process along with the reduce of the contents of sulfide source. The ester ligand was stable and led to the formation of high quality PbS NCs. The broad XRD diffraction peaks are typical of nanosized particles. The HRTEM images showed well-defined, near monodispersed cubic particles.