Structure and composition of guanidine acrylate, guanidine methacrylate, their homopolymers, and copolymers with diallyldimethylammonium chloride

Structures and compositions of the monomers guanidine acrylate and guanidine methacrylate, their homopolymers, and copolymers with diallyldimethylammonium chloride enriched in acrylate comonomer units were determined. It was shown that ampholytic copolymers, owing to their ionic nature, contained comonomeric guanidine acrylate or methacrylate units and diallyldimethylammonium chloride units, as well as the acrylate comonomer with the diallyl counterion and polymeric acrylate and diallyl ion pairs. It follows from IR and ¹H NMR data that guanidine methacrylate has the same structure (with two hydrogen bonds) in the solid state and in solutions. Guanidine acrylate structures in the solid state and in dimethylsulfoxide are identical and analogous to guanidine methacrylate structure in this solvent. In water, the guanidine acrylate structure has another type of hydrogen bonding (with one hydrogen bond, where the proton is shifted toward the guanidine group). These features of hydrogen bonding of guanidine acrylate and guanidine methacrylate are also retained in their homopolymers and copolymers with diallyldimethylammonium chloride. It was shown that the thermal stability of the copolymers was higher than that of their homopolymers, confirming the formation of intramolecular ion pairs of oppositely charged units of ampholytic copolymers. Moreover, the thermal stability of guanidine methacrylate-diallyldimethylammonium chloride copolymers is higher than that of guanidine acrylate-diallyldimethylammonium chloride copolymers.     

The Behavior of Polymers as Viscosity Index Improvers

Abstract

In the present work, six copolymers were prepared by reaction of 2-ethylhexyl methacrylate with vinyl acetate monomer by different molar ratio to produce copolymers (ν₁, ν₂, ν₃, ν₄, ν₅, and ν₆). The composition of these copolymers were determined by molecular weight (using Gel Permeation Chromatography (GPC) Water 600 E.) and by ¹HNMR (by 300 MHz Spectrometer w-P-300, Bruker) which indicate that the copolymers are alternating copolymers with reactivity ratio of 2-ethyl hexyl methacrylate is 0.65 and vinyl acetate is 0.51. The efficiency of the prepared copolymers as viscosity index improvers for lube oil was studies. From the data obtained, it was found that the efficiency as viscosity index improvers increases by increasing the molecular weight of the prepared polymers and increasing the concentration of these copolymers. The data were discussed on light of the chemical structure and reactivity ratio of the prepared copolymers.     

The synthesis and physicochemical parameters of new nonionic surfactants based on 1,2-propylene glycol,epichlorohydrin, and orthophosphoric acid

1,2-Propylene glycol has been chloroxypropylated with epichlorohydrin. The structures and compositions of synthesized oligomers having different average degrees of chloroxypropylation have been determined by IR and ¹H NMR spectroscopy. The physicochemical parameters of the oligomers have been determined, and their surface activity has been studied. The same characteristics have been found for 1,2-propylene glycol chloroxypropylates phosphatized with H₃PO₄. The ability of these products to retard the evaporation of gasoline during storage has been revealed.     

Biodegradation of Baku oil and hydrocarbons by micromycetes

Degradation of Baku oil, refinery products (diesel fuel, kerosene, and gasoline), and some individual aromatic hydrocarbons (toluene, p-xylene, and ethylbenzene) by micromycete cultures isolated from Caspian Sea water and coastal soil near the Apsheron peninsula was studied. The intensity of biodegradation of crude oil and petroleum products with micromycetes was determined by measuring carbon dioxide evolution and biomass formation. The conditions for chromatographic analyses of biodegradation products were determined. The dynamics of structure and composition of the test petrochemicals during oxidation with micromycetes was studied by means of gas-liquid and gas-solid chromatography and IR and ¹H NMR spectroscopy. It was found that, under cooxidizing conditions, microorganisms convert toluene and p-xylene into the corresponding monocarboxylic acids and acetophenone (35–40%) and phenylacetic acid (60–65%) are formed in the case of ethylbenzene.     

Synthesis and characterization of high molecular weight hydrophobically modified polyacrylamide nanolatexes using novel nonionic polymerizable surfactants

In this article, nine hydrophobically modified polyacrylamides (HM-PAM) nanolatexes, were synthesized by copolymerizing the acrylamide monomer and novel polymerizable surfactants (surfmers). The reaction was carried out by inverse microemulsion copolymerization technique. The copolymerization was initiated by redox initiators composed of potassium peroxodisulphate and sodium bisulfite. The emulsion was stabilized using mixed tween 85 and span 80 as nonionic emulsifiers. The prepared HM-PAMs were classified into three groups according to the surfmers used in the copolymerization. The chemical structures of the prepared HM-PAMs were confirmed by FT-IR, ¹H NMR and ¹³C NMR. The thermal properties were estimated with the thermal gravimetric analysis (TGA). The size and morphology of the prepared latexes were investigated by the dynamic light scattering (DLS) and the High Resolution Transmission Electron Microscope (HRTEM). Finally, the molecular weights of the prepared copolymers were determined by the GPC and the viscosity average molecular weight method. They were situated between 1.58 × 10⁶ and 0.89 × 10⁶.     

Enhanced Oil Recovery: The Synthesis of Anthraquinone [1, 2-C] Alkylisoxazole

Abstract

Anthraquinone [1, 2-C] methylisoxazole is synthesized from 2-ethylanthraquinone through nitration and treating with oleum. The different methods of 2-ethylanthraquinone nitrated were discussed. The optimum conditions were determined. The structure of the product was confirmed by MS and ¹H NMR.     

4-Aminoantipyrine derived cationic surfactants: Synthesis,characterization, surface activity and screening for potential antimicrobial activities

A series of cationic surfactants were synthesized from chemical modification of 4-aminoantipyrine. The chemical structures were confirmed using infrared (FTIR) and nuclear magnetic resonance (¹H NMR) spectroscopy. The surface activities of the surfactants in their solutions were determined by surface tension measurements. Increasing the hydrophobic chain length increased the surface activity of the surfactants in solutions. Measurements of interfacial tension between surfactants solutions and light paraffin oil showed that the interfacial tension values were decreased with increasing the alkyl chain length. The emulsion stability measurements showed the applicability of these surfactants as emulsifying agents. The foaming power measurements showed the synthesized surfactants have low ability for foam formation. Thermodynamic properties of adsorption and micellization processes showed their tendency towards adsorption at solution interface and micellization in their solutions. Results showed reasonable surface activities compared to conventional cationic surfactants. The antimicrobial activity of the synthesized surfactants against Gram-positive bacteria (Bacillus subtilis and Staphyl. aureus, Gram-negative bacteria (Pseudomonas aeruginosa and E. coli.) and Fungi (Candida albicans and Aspergillus niger) was evaluated. The efficiency of these compounds as antimicrobial agents) was increased with the hydrophobicity and carbon chain length.     

Double alkyl chain copolymers as flow improvers for heavy oil

As flow improvers for heavy crude oil, two oil-soluble copolymers (DM-S-VA, DA-S-VA) were successfully synthesized and characterized by ¹H NMR and GPC. A rich alkyl chain and appropriate molecular weight of copolymer play fundamental role in viscosity reduction of heavy oil. Furthermore, synergistic effect of surfactants on polymers can promote the viscosity reduction, and the best formulation can increase the viscosity reduction rate to 78% to oil A. Comparing with the apparent viscosity of the different heavy oil mixing system in a wide shear rate range (0.1–200 s^?1), the results show good stability and viscosity reducing effect.     

Synthesize and characterization of new polymeric surfactants based on nonionic maleate surfmer by catalytic bulk copolymerization with methyl methacrylate

Non-ionic maleate surfmer (M1) was prepared via ring opening reaction of maleic anhydride with hexanol followed by esterfaction with polyethylene glycol. The prepared surfmer was homo-polymerized and copolymerized with methyl methacrylate (M2) at different conditions using TiO₂ and V₂O₅ as catalysts in presence of O₂ or N₂. The chemical structure of the prepared surfmer, homo-polymer and copolymer were confirmed by FT-IR, ¹³C and ¹H NMR. The molecular weights of the prepared polymers were measured using Gel Permeation Chromatography (GPC) and their thermal gravimetric analysis (TGA) was determined. TGA indicated a higher thermal stability for the copolymers M1M2TN and M1M2VO relative to the pure polymethylmethacrylate (PMMA). The interfacial tension for the prepared surfmer and the copolymer was measured. The optimum conditions which resulted in 64.2% and 63.8% conversion were 20% w/w TiO₂ in N₂ and 10% w/w V₂O₅ in O₂ at 80?°C for 4?h with M1/M2 molar ratio of 1:1.     

1H NMR,Rheology, and Bottle Testing of HPAm/Cr(III) Acetate Micro Gels

Abstract

Solutions formulated at 40°C with partly hydrolyzed polyacrylamide (HPAm) and Cr(III) acetate 50% active were monitored for 240 hr using ¹H nuclear magnetic resonance (¹H NMR). The HPAm concentration was kept constant at 2,500 mg/L (which is slightly below the critical polymer concentration) and the HPAm to Cr(III) acetate weight ratio ranged from 5:1 to 60:1. Changes in the ¹H NMR transverse relaxation (T ₂) of the solutions were dominated by the chemistry of Cr(III) acetate. ¹H NMR detected changes immediately after HPAm started reacting with Cr(III) acetate. These changes were undetectable by rheology or bottle testing of the studied solutions.     

Optimization of phenol <Emphasis Type="Italic">ortho</Emphasis>-alkylation with styrene

The results of statistical treatment of experimental data on phenol alkylation with styrene in the presence of aluminum phenoxide as a catalyst are presented. The optimization of the process provides the maximum yield of 2,6-di-α-methylbenzylphenol. The structures of the synthesized compounds were determined on the basis of mass spectrometric, IR, and ¹H NMR data.     

Methanol to olefins conversion over silicoaluminophosphates with AEI structure: Effect of the active site type

Effect of the type of active site on the catalytic properties of microporous crystalline silicoaluminophosphates with AEI structure synthesized at 150, 170, and 190°C has been investigated. The state of the active site was changed by varying the catalyst synthesis conditions. It has been established that during the synthesis of silicoaluminophosphates with the AEI structure from the reaction mixture of the same composition, an increase in the temperature and crystallization time leads to an increase of the silicon content and crystal size growth. The observed changes in the physicochemical properties are accompanied by the change of the silicon state in the structure of silicoaluminophosphates with the predominant formation of silicon “islands” via the SM3 mechanism. According to ²⁹Si NMR data, the formation of active sites of silicoaluminophosphates via the SM2 mechanism in the form of isolated silicon atoms in the structure is also observed for these materials. The presence of such sites, along with the morphological features of the crystals, determines the unusual catalytic properties of silicoaluminophosphate with AEI structure in MTO process, which are a high ethylene yield up to 41 wt % at an ethylene: propylene molar ratio of 1: 6.     

功能化嵌段共聚物负载铜配合物的制备及其催化氧化性能

利用可逆-加成-断裂链转移自由基聚合的方法合成3种不同嵌段比的双亲水性嵌段共聚物聚甲基丙烯酸二甲氨乙酯-b-聚甲基丙烯酸酯聚乙二醇单甲醚-b-聚甲基丙烯酸二甲氨乙酯(PDMAEMA-b-POEOMA-b-PDMAEMA),将该共聚物与CuSO4或CuCl2配合,采用FTIR,1H NMR,TG,XRD方法对所得配合物的结构和组成进行表征。表征结果显示,阴离子种类(SO24-或Cl-)对配合物的结构及配位都有一定影响,而共聚物的嵌段比影响配合物的铜含量。采用Cu(Ⅱ)/Polymer-3/SO4配合物(Polymer-3:PDMAEMA39-b-POEOMA11-b-PDMAEMA39)催化苯乙烯氧化反应,在80℃、H2O2为氧化剂、m(苯乙烯)∶m(配合物)=200∶1、6 h的条件下,苯乙烯转化率87.8%,苯甲醛选择性82.1%。该催化剂循环使用3次,催化性能几乎不变。     

Composition and Properties of Some Petroleum Waxes

Abstract

Structural composition of paraffin waxes and soft wax fraction derived from microcrystalline wax were determined. Waxes were fractionated by multistage solvent crystallization at different temperatures. The n-alkane components of the waxes were separated by urea adduction. The average structural parameters of parent waxes, their fractions, and urea adductables were estimated by ¹h and ¹³C NMR spectroscopy. The thermal parameters viz. phase transition temperature and the associated energy during phase transitions were determined by using DSC and correlated with the penetration temperature behavior of waxes. The carbon number distribution determined by GC for these waxes and their n-alkane components were also correlated with physical properties and thermal parameters.     

Synthesis and Characterization of a New Claw Molecule as Diesel Low-Temperature Flow Improver

Abstract

Citric acid—neopentylene glycol—citric acid (CNC) triblock claw molecule as a fuel additive was applied as a diesel fuel low-temperature flow improver. Some of the other molecules—such as stearic acid and hexadecyl alcohol—are trapped with the above-synthesized claw molecule. The claw molecule, which is hydrophilic before the other molecules trapped into the suitable sites of the claw molecule, becomes soluble in diesel fuel. The claw molecule structure was further confirmed by ¹H NMR and IR spectra. The cold filter plugging point of diesel of adding the claw molecule was measured and discussed. The experimental results showed that the newly developed low-temperature flow improver has a good sensibility to diesel of different batches and different composition. When dosage is 600 μg/g, the reduction value of cold filter plugging point is up to 6 units.     

Synthesis of hydroxynitroalkyl esters and the study of their effect on the metabolism of sulfate-reducing bacteria

Novel hydroxynitroalkyl esters possessing bactericidal properties with respect to sulfate-reducing bacteria were synthesized. Optimal conditions for the synthesis of hydroxynitroalkyl esters were found, and their structure was confirmed by ¹H NMR and IR spectroscopy. It was shown that 3-acetoxy-2-hydroxy-2-methyl-1-nitro-and 4-pivaloxy-2-methyl-2-hydroxy-1-nitrobutane exhibit high antibacterial activity (50 mg/l) with respect to sulfate-reducing bacteria.     

A novel carbonate as a diesel fuel additive

A new oxygenate 2, 2^/-diethoxyethyl carbonate was synthesized through transesterification using dimethyl carbonate and ethylene glycol monoethyl ether as raw materials and its chemical structure was identified through FT-IR, ¹H NMR, and GC-MS analyses. The oxygenate is miscible with individual hydrocarbons at normal temperature. When 2, 2^/-diethoxyethyl carbonate is added to diesel fuel, kinematic viscosity decreases slightly, smoke point increases linearly, flash point and solidifying point decline remarkably even at low content level of 5%(v), whereas they do not decrease further with the increase in its content level. When a diesel engine was fueled with a diesel fuel containing 25%(v) of the oxygenate, the smoke emissions were reduced up to 83.3%, the energy consumption was decreased by up to 15.5%, whereas the power output dropped noticeably at high speed.     

Specifics of the group and homological compositions of aromatic hydrocarbons in some Azerbaijani crude oils

The distribution character and the composition of hydrocarbons in Azerbaijani oils of different types were studied. Concentrates of aromatic hydrocarbons were isolated from the 50° fractions of crude oils and oil residues boiling above 450°C. The structural-group composition of the isolated aromatic hydrocarbons was studied by spectral methods (mass spectrometry and ¹H NMR spectroscopy).     

Determination of the fractional composition of merchantable oil using quantitative <Superscript>1</Superscript>H NMR spectra

A simple method based on quantitative ¹H NMR data has been proposed for determining the fractional composition of merchantable oil.     

Structural Aspects of Crude Oil Derived Asphaltenes by NMR and XRD and Spectroscopic Techniques

Abstract

Asphaltene samples obtained from crude processed at two Indian refineries were characterized for chemical composition and structure by nuclear magnetic resonance (NMR), X-ray diffractometry (XRD), fluorescence spectroscopic techniques, and chromatographic (column and GPC) techniques. Estimation of NMR average structural parameters were obtained by combined ¹H, NMR ¹³C, NMR DEPT-45, and QUAT pulse sequence spectral editing techniques. The macrostructure and crystalline parameters of these samples were obtained by XRD. The nature of the functional groups have been obtained by IR technique. A combined NMR and XRD parameters were used to estimate the size of average aromatic structural units. Asphaltenes from one of the crudes (ASP-A) was found to be highly pericondensed, highly substituted, and higher molecular size compared to ASP-B asphaltene molecules. The number of aromatic sheets per unit sheets are 3.7 and 2.5 in the sample ASP-A and ASP-B, respectively. Both the asphaltene molecules in the samples have periodically and systematic arrangement of aromatic sheets in the unit sheet. The number of aromatic rings per unit sheet in ASP-A and ASP-B are 6.0 and 5.0, respectively. The fluorescence spectral studies has also exhibited λ _max (the wavelength of maximum intensity) at 505 and 509 nm confirming to pericondensed higher polycondensed aromatic ring system in both the samples. The analysis of liquid chromatographic fractions of these samples show that each sample is composed of several polycondensed aromatic systems where unit sheet of ring sizes vary from 1.8 to 6.3 with varying molecular sizes. These structural parameters allowed a model structure of the asphaltenes to be constructed.