Utilization of ethoxylated pentamine oleamide as new Gemini surfactants for corrosion inhibition effectiveness in 1 M HCl solution

This research aims to convert tetraethylene pentamine Gemini surfactants from oil to water-soluble corrosion inhibitors for applying in oil field at temperatures up to 65 °C. To achieve this aim, four new ethoxylated Gemini surfactants denoted as (T1, T2, T4 and T6) bearing different ethylene oxide units of 19, 28, 45 and 65, respectively were prepared and evaluated as corrosion inhibitors. The chemical structures of the prepared inhibitors were verified using FT-IR and 1H NMR spectroscopic analysis. The performance of the prepared surfactants was determined using surface tension measurements and thermodynamic parameters. Weight loss and electrochemical measurements were utilized to measure their corrosion inhibition efficiencies at a temperature range of 25–65 °C. Through the obtained results, the maximum inhibition efficiency of 95.74% was obtained by T6 at 25 °C in 1 M HCl. Keywords: Surfactants, Gemini surfactants, Corrosion inhibitors, Weight los

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

Solution properties of hydrophobically modified

We tested nine hydrophobically modified polyacrylamides with molecular weights situated between 1.58 and 0.89 × 106 g/mol for enhanced oil recovery applications. Their solution properties were investigated in the distilled water, brine solution, formation water and sea water. Their critical association concentrations were determined from the relationship between their concentrations and the corresponding apparent viscosities (ηapp) at 30 °C at shear rate 6 s−1. They were between 0.4 and 0.5 g/dl. The brine solutions of 0.5 g/dl of HM-PAMs were investigated at different conditions regarding their apparent viscosities. Such conditions were mono and divalent cations, temperature ranging from 30 to 90 °C, the shear rate ranging from 6 to 30 s−1 and the aging time for 45 days. The surface and interfacial tensions for the HM-PAMs were measured for concentration range from 0.01 to 1 g/dl brine solutions at 30 °C and their emulsification efficiencies were investigated for 7 days. The discrepancy in the properties and efficiencies of the tested copolymers was discussed in the light of their chemical structure

Formation of water-in-diesel oil nano-emulsions using high energy method and studying some of their surface active properties

In this work, formations of water-in-diesel oil nano-emulsions using water/mixed nonionic surfactant/diesel oil system have been studied. The high energy emulsification method was used to form three emulsions using different water contents: 5%, 10% and 14% (v/v) namely; E1, E2 and E3, respectively. These nano-emulsions were stabilized with emulsifiers having different Hydrophilic–Lipophilic Balance (HLB) namely; span 80 (HLB = 4.3), emarol 85 (HLB = 11) and their mixture (SE) with HLB = 10. The effect of water on the droplet size formation has been investigated. The interfacial tension and thermodynamic properties of the individual and emulsifiers blends have been studied. The interfacial tension (γ) measurements at 30 °C were used to determine the critical micelle concentration (CMC) and surface active properties of these emulsifiers. The water droplet sizes were measured by dynamic light scattering (DLS). From the obtained data, it was found that, mean sizes between 19.3 and 39 nm were obtained depending on the water content and concentration of blend emulsifiers (SE). Also, the results show that, the interfacial tension (γ) gives minimum value (10.85 mN/m) for SE comparing with individual emulsifier (17.13 and 12.77 mN/m) for span 80 and emarol 85, respectively. The visual inspection by TEM showed that the obtained results support the data obtained by dynamic light scattering

Synthesis of polyalkylacrylate nanolatexes by microemulsion polymerization method

The paper concerns with the radical polymerization of [octadecyl acrylate (ODA), isooctyl acrylate (iso-OA) and α-olefins 1-Octene (n-O)]. These microemulsions were stabilized by sodium dodecyl sulfate (SDS) and initiated by water-soluble initiator potassium persulfate (KPS). The nanolatex particle sizes were determined by transmission electron microscope (TEM). They were situated between 10 and 100 nm. The microstructures were confirmed by FT-IR and molecular weights determined by Gel permeation chromatography (GPC). The obtained M. wt. were (≈70 × 103, 101 × 103 and 153 × 103 g/mol). The polydispersity, molecular weights, and particle sizes were discussed in the light of micelle formation and shape of the alkyl group via emulsion polymerization

Water-in-diesel fuel nanoemulsions: Preparation, stability and physical properties

In this work, water-in-diesel fuel nanoemulsions were prepared with mixed nonionic surfactants. Several mixtures of sorbitan monooleate and polyoxyethylene (20) sorbitan monooleate, with different Hydrophilic–Lipophilic Balance (HLB) values (9.6, 9.8, 10, 10.2 and 10.4) were prepared to achieve the optimal HLB value. Three mixed surfactant concentrations were prepared at 6%, 8% and 10% to identify the optimum concentration. Five emulsions with different water contents: 5%, 6%, 7%, 8% and 9% (wt./wt.) were prepared using high energy method at the optimum conditions (HLB = 10 and mixed surfactant concentration = 10%). The effect of HLB value, mixed surfactant concentration and water content on the droplet size has been studied. The interfacial tension and thermodynamic properties of the individual and the blended emulsifiers were investigated. Droplet size of the prepared nanoemulsions was determined by dynamic light scattering and the nanoemulsion stability was assessed by measuring the variation of the droplet size as a function of time. From the obtained results, it was found that the mean droplet sizes were formed between 49.55 and 104.4 nm depending on HLB value, surfactant concentration and water content of the blended emulsifiers. The physical properties, kinematic viscosity and density, of the prepared nanoemulsions and the effect of different temperatures on these properties were measured

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background: The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods: In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results: Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89·6 per cent) compared with that in countries with a middle (753 of 1242, 60·6 per cent; odds ratio (OR) 0·17, 95 per cent c.i. 0·14 to 0·21, P < 0·001) or low (363 of 860, 42·2 per cent; OR 0·08, 0·07 to 0·10, P < 0·001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -9·4 (95 per cent c.i. -11·9 to -6·9) per cent; P < 0·001), but the relationship was reversed in low-HDI countries (+12·1 (+7·0 to +17·3) per cent; P < 0·001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0·60, 0·50 to 0·73; P < 0·001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion: Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background: End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods: This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results: In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion: Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone