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Abstrak :
Pembentukan kompleks Ni(II) dan 1,10-Phenanthroline (C12H8N2/Phen) dengan penambahan dithizone (C13H12N4S/HDz) pada antarmuka heksana-air telah dipelajari dengan metode spektrofotometri melalui pengukuran langsung dengan metode centrifugal liquid membrane (CLM). Ion Ni(II) dengan Phen membentuk kompleks kation Ni(C12H8N2) 22+atau NiPhen22+. Kompleks tersebut terlarut dalam fasa air serta memiliki dua panjang gelombang maksimum, λ maks yaitu 270 dan 292 nm. Pengamatan pembentukan kompleks dilakukan terhadap variasi pH dan konsentrasi ligan. Kondisi pH menyebabkan protonasi yang berpengaruh terhadap jumlah kompleks yang terbentuk. Pada variasi konsentrasi ligan, semakin besar konsentrasinya, jumlah kompleks yang terbentuk semakin banyak. Berdasarkan metode Batch, penambahan ligan HDz pada kompleks kation NiPhen 2 2+ menghasilkan kompleks asosiasi ion Ni(C13H11N4S)2(C12H8N2) atau NiDz 2Phen yang memilik iλ maks 403 nm, dan terekstrak dalam fasa organik. Hasil Pengukuran menggunakan metode CLM, diketahui kompleks NiDz2 Phen terbentuk pada antarmuka heksana-air dengan λ maks 523 nm. Perbandingan konsentrasi ligan Phen dengan HDz mempengaruhi laju awal pembentukan kompleks NiDz2 Phen. Semakin besar konsentrasi ligan Phen, laju awal pembentukan kompleks sinergis semakin cepat. Data yang diperoleh menggunakan metode CLM menunjukkan bahwa tetapan laju pembentukan kompleks sinergis NiDz2 Phen pada antarmuka, ksebesar 0,30 s-1.

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Abstract
Complex formation of Ni(II) and 1,10-phenanthroline (C12H8N2/Phen) with the addition of dithizone (C13H12N4S/HDz) at the hexane-water interface has been studied by direct measurement spectrophotometry using the centrifugal liquid membrane (CLM) method. Ni(II) ion with Phen formed a cationic complex of Ni(C12H8N2) 22+or NiPhen22+. That complex dissolved in the aqueous phase and had two UV absorption spectrum maxima wavelengths, λ max 270 and 292 nm. Observation of complex formation was performed variations of pH and ligand concentration. The pH caused protonation that affected the amount of the formed complex. With the variations of ligand concentrations, the greater was the concentration of ligands the greater was the formed complex. Based on the Batch method, the HDz ligand addition into the NiPhen 2 2+ cationic complex produced ionassociation complex of Ni(C13H11N4S)(C12H8N2) orNiDz2Phen atλ max 403 nm, and is extracted in the organic phase. Measurement results using CLM method showed that NiDz2 Phen complex was formed at hexane-water interface with λ max 523 nm. Comparison of Phen with HDz ligand concentrations affected the initial formation rate of NiDz2 Phen complex. The greater concentration of Phen ligand increased the initial rate of formation for synergistic complex. The obtained data using CLM method indicated that the synergistic complex formation rate constant of NiDz2 Phen at the interface, k was 0.30 s-1.

Abstrak :
Wax deposition can cause a serious problem in the distribution process of crude oil through a pipeline. At low temperatures, wax molecules can interact to form a wax aggregate. One way to reduce the wax aggregation is to introduce an additive compound into the crude oil. In this study, 15 crude oil models were prepared by mixing gasoline, kerosene, oil, wax, and asphaltene. Oxirane ester copolymer (OEC) additive was introduced into the crude oil models with various concentrations and volumes, and its effect on the crude oil models’ pour point and viscosity were evaluated. OEC interactions with wax and asphaltene were observed by FTIR, and the wax aggregation process was observed using cross polarized microscopy (CPM). The optimum pour point of crude oil was reached at a temperature of 6oC and optimum viscosity at 10 cSt for the selected model 4. OEC additions of 5% and 10% require 500 and 300 µL, respectively, to achieve the optima pour point and viscosity. OEC was able to inhibit the wax aggregation, as evidenced from the interaction between OEC-wax at 722 cm-1 and OEC-asphaltene at 1604 and 1494 cm-1 of FTIR spectra. The distribution of the wax aggregate was observed using CPM, with the value of the wax appearance temperature (WAT) at 28.7oC. This research can be the basis for designing or selecting a molecule for use as a pour point depressant in accordance with the characteristics of crude oil, particularly since each source of crude oil has different characteristics.