Decrease In Cloud Point Research Articles

Production of Fuel Oil from Blends of Refinery Products for Powering Heat Exchanger

Fuel oil, also known as furnace oil is a fraction of crude oil obtained when distillation processing is carried out in the refinery. Due to the high viscous of the heavy fuel oil, that makes it difficult to be pump throughout the pipework of the power plant, it is necessary to produce a fuel oil that will meet up the required standard. The aim of this study was to produce fuel oil from the blend of refinery intermediate product which meet certain European fuel specifications outlined in the EN 590:2009 standard alongside NMDPRA Standards. The blending stocks obtained from the Warri Refinery and Petrochemical Company (WRPC) were first filtered to remove some particulate impurities before they were analyzed to determine their properties after which, they were introduced into a mixed-tank that has an agitator connected and the blending was done using the blending ratio obtained from literature. The fuel oil produced was eventually analyzed for properties such as: Specific Gravity, API Gravity, Density, Viscosity, Kinematic Viscosity, Moisture Content, Flash Point, Cloud Point, Pour Point and Sulphur content. The sample with a composition of 33.3% of Decant oil (DCO), 33.3% Heavy gas oil (HGO), 33.3% light cycle oil (LCO) produced fuel oil of specific gravity 0.916, API Gravity 22.95, Density 0.896, Viscosity 40, Kinematic viscosity 4.7, pour point -6.5 and flash point 109, The analysis of the fuel oil meet the standard for blended fuel oil, according to the ISO 8217:2017 Standard. The results confirmed that blending of decant oil with conventional petroleum diesel (heavy and light gas oil) has a highly significant effect on the properties of the resulting fuel blend. The results show that by increasing the heavy gas oil content of the blend, the flash point of the blend increases; while increasing the decant oil content of the blend results in a decrease in Cloud point. The results of the analysis of the produced fuel oil confirms that its properties fall within the acceptable range for Fuel Oil and can be used as fuel for fired heaters and furnaces of the refinery and other process plants.

Topology and Sequence-Dependent Micellization and Phase Separation of Pluronic L35, L64, 10R5, and 17R4: Effects of Cyclization and the Chain Ends.

The topology effects of cyclization on thermal phase transition behaviors were investigated for a series of amphiphilic Pluronic copolymers of both hydrophilic–hydrophobic–hydrophilic and hydrophobic–hydrophilic–hydrophobic block sequences. The dye solubilization measurements revealed the lowered critical micelle temperatures (TCMT) along with the decreased micellization enthalpy (ΔHmic) and entropy (ΔSmic) for the cyclized species. Furthermore, the transmittance and dynamic light scattering (DLS) measurements indicated a block sequence-dependent effect on the clouding phenomena, where a profound decrease in cloud point (Tc) was only found for the copolymers with a hydrophilic–hydrophobic–hydrophilic block sequence. Thus, the effect of cyclization on these critical temperatures was manifested differently depending on its block sequence. Finally, a comparison of the linear hydroxy-terminated, methoxy-terminated, and cyclized species indicated the effect of cyclization to be unique from a simple elimination of the terminal hydrophilic moieties.

UV-tunable upper critical solution temperature behavior of azobenzene containing poly(methyl methacrylate) in aqueous ethanol

A series of azobenzene containing copolymers were synthesized by post-modification of poly(methyl methacrylate-co-pentafluorophenyl methacrylate) with an amine-functionalized azobenzene. Light- and thermo-responsive behavior of these copolymers was investigated in ethanol–water solvent mixtures with various amounts of ethanol. The upper critical solution temperature (UCST) of the polymer solutions, resulting from the poly(methyl methacrylate), was found to be highly tunable by the substitution degree of the copolymers as well as the ethanol content of the solvent mixture. In addition, the copolymers are light responsive based on the cis–trans isomerization of the azobenzene group under UV irradiation. The cloud point temperatures (TCP) of the polymer solutions decreased after UV-irradiation due to the higher dipole moment of the cis-isomer of the azobenzene moiety leading to better solubility in ethanol–water solvent mixtures. Furthermore, the UV responsiveness was found to strongly depend on the solvent composition, revealing a higher decrease in cloud point after UV-irradiation in ethanol–water solvent mixture with higher water content. To the best of our knowledge, this is the first reported dual responsive polymer that combines light responsiveness with UCST behavior in aqueous solvent mixtures.

Energetics of Clouding Phenomenon in Amphiphilic Drug Imipramine Hydrochloride with Pharmaceutical Excipients

The clouding behaviour of an amphiphilic antidepressant drug imipramine hydrochloride (IMP) with several additives (hydrotropes, bile salts, fatty acids and sugars) over the entire composition range at pH = 7.6 was investigated in the present study. The magnitude of clouding (increase or decrease) of IMP in the presence of additives (pharmaceutical excipients) depends on the nature and types of additives. Bile salts and fatty acids showed peak behaviour i.e., cloud point (CP) increases at lower concentrations while decrease in cloud points was observed at higher concentrations. Thermodynamics at the CP were also evaluated (except for sugars, because sugars does not form mixed micelles with IMP), assuming that the clouding indicates the solubility limit when phase separation occurs. Thus, the various thermodynamic parameters e.g., standard Gibbs free energy (ΔG ), the enthalpy (ΔH ) and entropy (TΔS ) were calculated at this point. The results showed that the ΔG , was found to be negative for all the additives, however ΔH and TΔG of the clouding phenomenon were found to be positive or negative depending upon the types and nature of additives.

Interactions between hairy rod anionic conjugated polyelectrolytes and nonionic alkyloxyethylene surfactants in aqueous solution: Observations from cloud point behaviour

The effect of three anionic, hairy-rod fluorene based conjugated polyelectrolytes on the cloud points of the alkyloxyethylene surfactants C10E3, C12E4, C12E5, and C12E6 has been studied in aqueous solution. Although the association behaviour of these rigid polymers with surfactants is different from that of more flexible polyelectrolytes, both types of polymers are seen to increase the cloud points, probably as a consequence of associative interactions. The possible importance of Coulombic interactions is suggested by the decrease in cloud points with these systems in the presence of NaCl. With the conjugated polyelectrolytes, the effect appears to be most pronounced with poly[9,9-bis(4-phenoxybutylsulfonate)fluorene-co-2,5-thienylene], which may result from specific interactions between oxyethylene groups and the thiophene ring. The value of cloud point behaviour in designing water based formulations for preparation of devices of these conjugated polyelectrolytes is discussed.

Effect of different additives on the cloud point of a polyethylene oxide‐polypropylene oxide‐polyethylene oxide block copolymer in aqueous solution

AbstractCloud point studies on aqueous solutions of a polyethylene oxide (PEO)‐polypropylene oxide‐PEO triblock copolymer (Pluronic® L64: EO13PO30EO13, total m.w.=2900, PEO=40%; EO=ethylene oxide; PO=propylene oxide) in the presence of different additives show some interesting features. The effect of various inorganic salts was an increase or decrease in cloud point based on their salting in and salting out action and followed the Hofmeister lyotropic series. Nonelectrolytes and hydrotropes increased the cloud point by influencing water structure. Hydrotropes altered the cloud point of the copolymer at much lower concentrations than inorganic salts. Ionic surfactants produced a marked increase in the cloud point of copolymer solutions. The effect was greater for surfactants with greater hydrophobicity. Alcohols and other organic liquid additives that are infinitely miscible with water increase the cloud point of the copolymer, whereas additives that are partially miscible in water decrease the cloud point.

Solution behavior of a surfactant aldehyde–the oxidation product of an alcohol ethoxylate

It has previously been shown that alcohol ethoxylates readily undergo autoxidation and that one of the major oxidation products is the surfactant aldehyde, i.e. an ethoxylate carrying a –CH 2CHO group at the terminal end of the polyoxyethylene chain. In this work the cloud point, phase behavior and aggregation characteristics of the surfactant aldehyde produced by oxidation of C 12H 25(OCH 2CH 2) 5OH (C 12E 5) are determined and compared with the values obtained with the parent surfactant. It was found that the physico–chemical behavior of the two species was very similar, which indicates that a considerable portion of the aldehyde group is in hydrated state, i.e. the surfactant aldehyde consists of a mixture of aldehyde in carbonyl form and the corresponding geminal diol. The cloud point of the surfactant aldehyde decreased rapidly with time, even when it was stored at low temperature. Also the parent surfactant and its homologue C 12E 6 exhibited a decrease in cloud point during storage. For instance, a 1% aqueous solution of C 12E 6 showed a cloud point decrease from 62 to 32°C after 4 months storage at 40°C. Such a change in solution behavior can have important practical implications.

Structural Effects of Aminimide Derivatives on Their Surface Active Properties and Phase Transfer Catalytic Actions

Several new series of aminimides [(3ac, e), (4ah), (5d) and (6a, b) in Scheme-1] were synthesized by Slagel method1). Some surface active properties and the effectiveness on phase transfer catalysis were examined for these compounds. The results were compared with those of several reference compounds.Surface active properties of aminimides (1ae)5) and (2ag)2), and bis(aminimides) (5ac)3) have been reported previously. Substitution of an aromatic group, especially pyridyl group, for an alkyl group (C23) on imino nitrogen of aminimides caused a decrease in cloud point (Cp) and critical micelle concentration (cmc), but an increase in melting point, Krafft point (Kp) and γcmc (surface tension above cmc). Melting point, Cp and γcmc increased with increasing the number of hydroxyl group in an amineimide molecule regardless of the relative position (Table-2). In the case of bis(aminimides), (6a) was similar to (5d), but differed from (6b) regarding to the dissolution behavior (Kp and Cp) (Table-3).It was found that the efficiency of aminimides as phase transfer catalysts in the substitution reaction of 1-bromooctane with aqueous potassium iodide depended on the following structural factors: a) HLB (hydrophilic-lipophilic balance) of aminimides, b) the position on which long chain placed (_??_+N- and/or -N-), c) the number of hydroxyl groups, d) introduction of pyridyl group, and e) the chain length and the steric structure of the linking group between two aminimide groups in bis(aminimides). The series (1) were the most effective among the series examined, and some of (1) had a high efficiency close to that of “Dicyclohexyl-18-crown-6” (Table-4).

Cross-linked hydrophilic gels from ABA block copolymeric surfactants

Gelation of aqueous solutions of poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) block co-polymeric non-ionic Surfactants (Pluronics or poloxamers) by the action of γ-rays is reported. Poloxamers with ethylene oxide content below 70% do not gel under the conditions studied, but appear to undergo chain scission, as there is a decrease in cloud point and an increase in hydrodynamic radius which is most likely to be due to increased association of the more hydrophobic polymer. The gels obtained from poloxamers with ethylene oxide content over 70% have a high water uptake capacity. The possibility of using these gels as sustained release drug delivery systems is discussed.