Nehal Ahmed - Academia.edu (original) (raw)
Papers by Nehal Ahmed
Esters have been used successfully in lubrication for more than 60 years and are the preferred st... more Esters have been used successfully in lubrication for more than 60 years and are the preferred stock in many severe applications where their benefits solve problems. In many ways esters are very similar to the more commonly known and used synthetic hydrocarbons. In the present work, the different mixed esters were prepared by reaction of pentaerythritol with different ratio of butyric acid and octanoic acid. Structure of the prepared compounds was confirmed by study the physico-chemical properties as (Infra-Red Spectroscopy, Nuclear Magnetic Resonance, Thermo Gravimetric Analysis TGA, Total Acid Number, density, reflective index, specific gravity, flash point and the Determination of the Molecular Weights) for all the prepared compounds. The efficiency of the prepared compounds were investigated as synthetic refrigeration lubricating oil. It was found that the prepared compounds have low temperature properties (pour point), high viscosity index (VI) and the rheological behavior is s...
In the present work, some antioxidants lube oil additives based on zinc dialkyl di thiophosphate ... more In the present work, some antioxidants lube oil additives based on zinc dialkyl di thiophosphate were prepared by two steps, the first step is the reaction of different alcohols (n-butyl, isobutyl and mixture of isobutyl and amyl) with phosphorus pentasulphide to prepare O, O `-dialkyldithiophosphoric acid (DPDA), second step is the product dialkyldithiophosphoric acid (DPDA) was neutralized with zinc oxide. The structures of the prepared compounds were confirmed by Infra-Red Spectroscopy, Elemental Analysis and Determination of the molecular weights by using Gel Permeation C hromatography (GPC). All the prepared compounds were soluble in lube oil. The efficiency of the prepared compounds as antioxidants lube oil additives was investigated. It was found that the prepared compounds based on mixture of isobutyl and amyl alcohol give the best results as antioxidant lube oil additives. The Quantum mechanical parameters such as the highest occupied molecular orbital (HOMO), the lowest un...
Different Mannich base compounds based on polyisobutylene succinic anhydride (PIBSA) were prepare... more Different Mannich base compounds based on polyisobutylene succinic anhydride (PIBSA) were prepared. The structures of the prepared compounds were confirmed using Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance (1 H-NMR) and Gel Permeation Chromatography (GPC) for determination of molecular weight. The efficiency of the prepared compounds as antioxidants and detergents/dispersants were studied. It was found that the efficiency of the prepared compounds as dispersants increases with increasing the number of NH group. It was found that Mannich base compounds are more efficient as dispersants than that before Mannich base formation, and the efficiency of the prepared compounds as antioxidants increases by increasing the number of NH group. The Mannich base formation leads to enhanced efficiency as antioxidants than compounds before Mannich base.
Due to increasing the global awareness towards the environment, six eco-friendly bio-based terpol... more Due to increasing the global awareness towards the environment, six eco-friendly bio-based terpolymers based on (jojoba – vinyl acetate α-olefin) and (Jojoba – vinyl pyrrolidone α-olefin) were synthesized via free radical polymerization using (1:1:1) molar ratios. They were elucidated using FT-IR, H-NMR, GPC and their thermal stabilities were determined. The prepared terpolymers (A1-A3) and (B1-B3) were evaluated as performance additives for lube oil (SAE-30) free of additives, and it was found that the prepared terpolymers possess a dual effect on untreated lube oil (as viscosity modifiers and pour point depressants).
Egyptian Journal of Chemistry, 2021
Esters have many important properties, such as biodegradation, low toxicity, good thermal stabili... more Esters have many important properties, such as biodegradation, low toxicity, good thermal stability and excellent solvability, because these features are definitely the most versatile of the various types of base fluids currently available and can be modified to provide unique physical and chemical properties that can be designed to meet the lubricant industry's challenges. In this article, Reaction was prepared by various branched synthetic esters of 2-ethyl hexanoic acid with different 2 groups of alcohols, the first one (1-hexanol, 2-ethyl hexanol,1-octanol, 1-dodecanol and 1-hexadecanol), and the second group (neopentyl glycol, trimethylol propane and pentaerythritol). All the preparation compound form were confirmed by examine the physical and chemical properties as (Nuclear Magnetic Resonance, Infra-Red Spectroscopy, Total Acid Number, Density, Thermo Gravimetric Analysis TGA, Specific gravity, Reflective index, Molecular weights estimation and flash point). As a synthetic lubricating oil, the performance of these compounds was studied. Prepared compounds have been found to contain low pour point (PP), high viscosity level (VI) and Newtonian fluid for rheological behavior.
Seven terpolymers were synthesized and evaluated as lubricating oil additives. The synthesis proc... more Seven terpolymers were synthesized and evaluated as lubricating oil additives. The synthesis process occurs via esterification reaction of acrylic acid with (octanol, decanol, dodecanol, tetradecanol, hexadecanol, octadecanol and docosanol) separately. Then polymerization of each ester with vinyl acetate and 1-tetradecene were carried out. The prepared compounds were elucidated by using FTIR (Fourier Transform Infrared Spectroscopy), H-NMR (Proton Nuclear Magnetic Resonance), and the molecular weight was determined by using GPC (Gel Permeation Chromatography). The efficiency of the prepared terpolymers as viscosity index improvers and pour point depressants for lubricating oil was investigated and compared with that of the mineral base oils, it was found that the viscosity index increases with increasing the concentration of the prepared compounds, and with increasing the alkyl chain length of the alkylacrylate used from octylacrylate till tetradecylacrylate, then decreases with inc...
Petroleum and Coal
Jojoba homopolymer was prepared, elucidated, and evaluated as lube oil additive, then novel six c... more Jojoba homopolymer was prepared, elucidated, and evaluated as lube oil additive, then novel six copolymers were prepared via reaction of jojoba oil as a monomer with different alkylacrylate, (dodecylacrylate, tetradecyacrylate, and hexadecyacrylate), and with different α – olefins (1-dodecene, 1-tetradecene, and 1-hexadecene), separately with (1:2) molar ratio. The prepared polymers were elucidated using Proton Nuclear Magnetic Resonance (1H-NMR) and Gel Permeation Chromatography (GPC), for determination of weight average molecular weight (Mw), and the thermal stability of the prepared polymers was determined. The prepared polymers were evaluated as viscosity index improvers and pour point depressants for lubricating oil. It was found that the viscosity index increases with increasing the alkyl chain length of both α- olefins, and acrylate monomers, while the pour point improved for additives based on alkyl acrylate.
Applied Petrochemical Research, 2013
In the present work, some Mannich bases have been prepared by using different polyethylenepolyami... more In the present work, some Mannich bases have been prepared by using different polyethylenepolyamines. Phosphosulphurized Mannich bases have been also prepared by reaction of prepared Mannich bases with P 2 S 5. Structure of the prepared compounds was confirmed by infrared spectroscopy and the molecular weights determination. The efficiency of the prepared additives as antioxidants and detergents/dispersants was investigated. It was found that the efficiency increases with increasing the NH groups in the amine used. The best prepared additive as antioxidant and detergent/dispersant was obtained by using triethylenetetramine.
Applied Petrochemical Research, 2014
Nine terpolymers consisting of (jojoba: alkylacrylate: a-olefins) backbone were synthesized via f... more Nine terpolymers consisting of (jojoba: alkylacrylate: a-olefins) backbone were synthesized via free radical chain addition polymerization and determined using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and gel permeation chromatography, for determination of weight average molecular weight. The alkylacrylates used were (dodecylacrylate, tetradecylacrylate and hexadecylacrylate), while a-olefins used were (dodecene, tetradecene and hexadecane). The monomers' ratio used for polymerization was (1:1:1). It was found that the molecular weight increases with increasing the alkyl chain length of both alkylacrylate and a-olefins used. The thermal stability of the synthesized terpolymers was determined using thermal gravimetric analysis and differential scanning calorimetry. The prepared polymers were evaluated as performance modifiers (viscosity index improvers and pour point depressants) for free additives lube oil (SAE-30). It was found that the viscosity index increases with increasing the alkyl chain length, molecular weight and concentration of used terpolymer. The effect of the prepared terpolymers on the pour point of lube oil was studied and it was found that the pour point of lube decreases (more negative) with decreasing the alkyl chain length of both alkylacrylate and a-olefin used.
Petroleum Science and Technology, 2005
Page 1. Petroleum Science and Technology, 23: 537546, 2005 Copyright © Taylor &a... more Page 1. Petroleum Science and Technology, 23: 537546, 2005 Copyright © Taylor & Francis, Inc. ISSN 1091-6466 print/1532-2459 online DOI: 10.1081/LFT-200031097 Preparation and Evaluation of Acrylate Polymers as Viscosity Index Improvers for Lube Oil ...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2003
In the present work, five surfactants were prepared; two of them were monomeric surfactants, one ... more In the present work, five surfactants were prepared; two of them were monomeric surfactants, one was anionic (triethanol ammonium salt of dodecyl benzene sulfonic acid, E 1) and the second was non-ionic surfactant (nonyl phenol ethoxylate,E 2). The other three surfactants were polymeric non-ionic surfactants (ethoxylated polynonyl phenol formaldehyde mono-ethanol amine E 3 , ethoxylated poly nonyl phenol formaldehyde diethanol amine E 4, and ethoxylated nonoyl phenol formaldehyde triethanol amine E 5). The gel permeation chromatography (GPC) and the elemental analysis were carried out to determine the molecular weight of the polymeric surfactants. The surface properties for these surfactants were determined by measuring the surface tension, the interfacial tension, the foaming power, cloud point and the emulsification power. The polymeric surfactants were used to treat the polluted sandy soil, which saturated with two types of crude oils (waxy and asphaltenic). From the data obtained it was found that, the increasing of surfactant concentrations led to increase the reclaimation of the waxy and asphaltinic crude oil percentages and decreased the interfacial tension. The reclaimed oil percentage increased with decreasing the hydrophilic-lipophilic balance (HLB) value of non-ionic surfactant. In general behavior, the reclamation of the asphaltenic crude oil was greater than the reclaimation of the waxy crude oil. The data were discussed on light of the chemical structure of the surfactants and composition of crude oil.
Petroleum Science and Technology, 2000
Page 1. PETROLEUM SCIENCE ANDTECHNOLOGY, 18(9&10), 1175-1193 (2000) SODIUM LIGNIN SULFONATE T... more Page 1. PETROLEUM SCIENCE ANDTECHNOLOGY, 18(9&10), 1175-1193 (2000) SODIUM LIGNIN SULFONATE TO STABILIZE HEAVY CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION NAEL N. ZAKI ...
Surface Science, 1989
The interaction of dysprosium metal atoms with silicon (111) surface at different temperatures ha... more The interaction of dysprosium metal atoms with silicon (111) surface at different temperatures has been investigated using X-ray photoelectron spectroscopy and X-ray diffraction analysis. Si 2p and Dy 3d5/2 spectral lines are used to propose the Dy-Si interaction in the interface region. Even at room temperature (300 K) strong interaction between Dy and Si atoms takes place due to charge transfer from Dy to Si. At this temperature, at the interface, a predominantly Dy-rich DysSi 3 phase is observed. Whereas at an annealing temperature of 623 K a silicon-rich DySi2 phase is observed. At an intermediate temperature of 423 K both these phases are seen with some amorphous background.
Esters have been used successfully in lubrication for more than 60 years and are the preferred st... more Esters have been used successfully in lubrication for more than 60 years and are the preferred stock in many severe applications where their benefits solve problems. In many ways esters are very similar to the more commonly known and used synthetic hydrocarbons. In the present work, the different mixed esters were prepared by reaction of pentaerythritol with different ratio of butyric acid and octanoic acid. Structure of the prepared compounds was confirmed by study the physico-chemical properties as (Infra-Red Spectroscopy, Nuclear Magnetic Resonance, Thermo Gravimetric Analysis TGA, Total Acid Number, density, reflective index, specific gravity, flash point and the Determination of the Molecular Weights) for all the prepared compounds. The efficiency of the prepared compounds were investigated as synthetic refrigeration lubricating oil. It was found that the prepared compounds have low temperature properties (pour point), high viscosity index (VI) and the rheological behavior is s...
In the present work, some antioxidants lube oil additives based on zinc dialkyl di thiophosphate ... more In the present work, some antioxidants lube oil additives based on zinc dialkyl di thiophosphate were prepared by two steps, the first step is the reaction of different alcohols (n-butyl, isobutyl and mixture of isobutyl and amyl) with phosphorus pentasulphide to prepare O, O `-dialkyldithiophosphoric acid (DPDA), second step is the product dialkyldithiophosphoric acid (DPDA) was neutralized with zinc oxide. The structures of the prepared compounds were confirmed by Infra-Red Spectroscopy, Elemental Analysis and Determination of the molecular weights by using Gel Permeation C hromatography (GPC). All the prepared compounds were soluble in lube oil. The efficiency of the prepared compounds as antioxidants lube oil additives was investigated. It was found that the prepared compounds based on mixture of isobutyl and amyl alcohol give the best results as antioxidant lube oil additives. The Quantum mechanical parameters such as the highest occupied molecular orbital (HOMO), the lowest un...
Different Mannich base compounds based on polyisobutylene succinic anhydride (PIBSA) were prepare... more Different Mannich base compounds based on polyisobutylene succinic anhydride (PIBSA) were prepared. The structures of the prepared compounds were confirmed using Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance (1 H-NMR) and Gel Permeation Chromatography (GPC) for determination of molecular weight. The efficiency of the prepared compounds as antioxidants and detergents/dispersants were studied. It was found that the efficiency of the prepared compounds as dispersants increases with increasing the number of NH group. It was found that Mannich base compounds are more efficient as dispersants than that before Mannich base formation, and the efficiency of the prepared compounds as antioxidants increases by increasing the number of NH group. The Mannich base formation leads to enhanced efficiency as antioxidants than compounds before Mannich base.
Due to increasing the global awareness towards the environment, six eco-friendly bio-based terpol... more Due to increasing the global awareness towards the environment, six eco-friendly bio-based terpolymers based on (jojoba – vinyl acetate α-olefin) and (Jojoba – vinyl pyrrolidone α-olefin) were synthesized via free radical polymerization using (1:1:1) molar ratios. They were elucidated using FT-IR, H-NMR, GPC and their thermal stabilities were determined. The prepared terpolymers (A1-A3) and (B1-B3) were evaluated as performance additives for lube oil (SAE-30) free of additives, and it was found that the prepared terpolymers possess a dual effect on untreated lube oil (as viscosity modifiers and pour point depressants).
Egyptian Journal of Chemistry, 2021
Esters have many important properties, such as biodegradation, low toxicity, good thermal stabili... more Esters have many important properties, such as biodegradation, low toxicity, good thermal stability and excellent solvability, because these features are definitely the most versatile of the various types of base fluids currently available and can be modified to provide unique physical and chemical properties that can be designed to meet the lubricant industry's challenges. In this article, Reaction was prepared by various branched synthetic esters of 2-ethyl hexanoic acid with different 2 groups of alcohols, the first one (1-hexanol, 2-ethyl hexanol,1-octanol, 1-dodecanol and 1-hexadecanol), and the second group (neopentyl glycol, trimethylol propane and pentaerythritol). All the preparation compound form were confirmed by examine the physical and chemical properties as (Nuclear Magnetic Resonance, Infra-Red Spectroscopy, Total Acid Number, Density, Thermo Gravimetric Analysis TGA, Specific gravity, Reflective index, Molecular weights estimation and flash point). As a synthetic lubricating oil, the performance of these compounds was studied. Prepared compounds have been found to contain low pour point (PP), high viscosity level (VI) and Newtonian fluid for rheological behavior.
Seven terpolymers were synthesized and evaluated as lubricating oil additives. The synthesis proc... more Seven terpolymers were synthesized and evaluated as lubricating oil additives. The synthesis process occurs via esterification reaction of acrylic acid with (octanol, decanol, dodecanol, tetradecanol, hexadecanol, octadecanol and docosanol) separately. Then polymerization of each ester with vinyl acetate and 1-tetradecene were carried out. The prepared compounds were elucidated by using FTIR (Fourier Transform Infrared Spectroscopy), H-NMR (Proton Nuclear Magnetic Resonance), and the molecular weight was determined by using GPC (Gel Permeation Chromatography). The efficiency of the prepared terpolymers as viscosity index improvers and pour point depressants for lubricating oil was investigated and compared with that of the mineral base oils, it was found that the viscosity index increases with increasing the concentration of the prepared compounds, and with increasing the alkyl chain length of the alkylacrylate used from octylacrylate till tetradecylacrylate, then decreases with inc...
Petroleum and Coal
Jojoba homopolymer was prepared, elucidated, and evaluated as lube oil additive, then novel six c... more Jojoba homopolymer was prepared, elucidated, and evaluated as lube oil additive, then novel six copolymers were prepared via reaction of jojoba oil as a monomer with different alkylacrylate, (dodecylacrylate, tetradecyacrylate, and hexadecyacrylate), and with different α – olefins (1-dodecene, 1-tetradecene, and 1-hexadecene), separately with (1:2) molar ratio. The prepared polymers were elucidated using Proton Nuclear Magnetic Resonance (1H-NMR) and Gel Permeation Chromatography (GPC), for determination of weight average molecular weight (Mw), and the thermal stability of the prepared polymers was determined. The prepared polymers were evaluated as viscosity index improvers and pour point depressants for lubricating oil. It was found that the viscosity index increases with increasing the alkyl chain length of both α- olefins, and acrylate monomers, while the pour point improved for additives based on alkyl acrylate.
Applied Petrochemical Research, 2013
In the present work, some Mannich bases have been prepared by using different polyethylenepolyami... more In the present work, some Mannich bases have been prepared by using different polyethylenepolyamines. Phosphosulphurized Mannich bases have been also prepared by reaction of prepared Mannich bases with P 2 S 5. Structure of the prepared compounds was confirmed by infrared spectroscopy and the molecular weights determination. The efficiency of the prepared additives as antioxidants and detergents/dispersants was investigated. It was found that the efficiency increases with increasing the NH groups in the amine used. The best prepared additive as antioxidant and detergent/dispersant was obtained by using triethylenetetramine.
Applied Petrochemical Research, 2014
Nine terpolymers consisting of (jojoba: alkylacrylate: a-olefins) backbone were synthesized via f... more Nine terpolymers consisting of (jojoba: alkylacrylate: a-olefins) backbone were synthesized via free radical chain addition polymerization and determined using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and gel permeation chromatography, for determination of weight average molecular weight. The alkylacrylates used were (dodecylacrylate, tetradecylacrylate and hexadecylacrylate), while a-olefins used were (dodecene, tetradecene and hexadecane). The monomers' ratio used for polymerization was (1:1:1). It was found that the molecular weight increases with increasing the alkyl chain length of both alkylacrylate and a-olefins used. The thermal stability of the synthesized terpolymers was determined using thermal gravimetric analysis and differential scanning calorimetry. The prepared polymers were evaluated as performance modifiers (viscosity index improvers and pour point depressants) for free additives lube oil (SAE-30). It was found that the viscosity index increases with increasing the alkyl chain length, molecular weight and concentration of used terpolymer. The effect of the prepared terpolymers on the pour point of lube oil was studied and it was found that the pour point of lube decreases (more negative) with decreasing the alkyl chain length of both alkylacrylate and a-olefin used.
Petroleum Science and Technology, 2005
Page 1. Petroleum Science and Technology, 23: 537546, 2005 Copyright © Taylor &a... more Page 1. Petroleum Science and Technology, 23: 537546, 2005 Copyright © Taylor & Francis, Inc. ISSN 1091-6466 print/1532-2459 online DOI: 10.1081/LFT-200031097 Preparation and Evaluation of Acrylate Polymers as Viscosity Index Improvers for Lube Oil ...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2003
In the present work, five surfactants were prepared; two of them were monomeric surfactants, one ... more In the present work, five surfactants were prepared; two of them were monomeric surfactants, one was anionic (triethanol ammonium salt of dodecyl benzene sulfonic acid, E 1) and the second was non-ionic surfactant (nonyl phenol ethoxylate,E 2). The other three surfactants were polymeric non-ionic surfactants (ethoxylated polynonyl phenol formaldehyde mono-ethanol amine E 3 , ethoxylated poly nonyl phenol formaldehyde diethanol amine E 4, and ethoxylated nonoyl phenol formaldehyde triethanol amine E 5). The gel permeation chromatography (GPC) and the elemental analysis were carried out to determine the molecular weight of the polymeric surfactants. The surface properties for these surfactants were determined by measuring the surface tension, the interfacial tension, the foaming power, cloud point and the emulsification power. The polymeric surfactants were used to treat the polluted sandy soil, which saturated with two types of crude oils (waxy and asphaltenic). From the data obtained it was found that, the increasing of surfactant concentrations led to increase the reclaimation of the waxy and asphaltinic crude oil percentages and decreased the interfacial tension. The reclaimed oil percentage increased with decreasing the hydrophilic-lipophilic balance (HLB) value of non-ionic surfactant. In general behavior, the reclamation of the asphaltenic crude oil was greater than the reclaimation of the waxy crude oil. The data were discussed on light of the chemical structure of the surfactants and composition of crude oil.
Petroleum Science and Technology, 2000
Page 1. PETROLEUM SCIENCE ANDTECHNOLOGY, 18(9&10), 1175-1193 (2000) SODIUM LIGNIN SULFONATE T... more Page 1. PETROLEUM SCIENCE ANDTECHNOLOGY, 18(9&10), 1175-1193 (2000) SODIUM LIGNIN SULFONATE TO STABILIZE HEAVY CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION NAEL N. ZAKI ...
Surface Science, 1989
The interaction of dysprosium metal atoms with silicon (111) surface at different temperatures ha... more The interaction of dysprosium metal atoms with silicon (111) surface at different temperatures has been investigated using X-ray photoelectron spectroscopy and X-ray diffraction analysis. Si 2p and Dy 3d5/2 spectral lines are used to propose the Dy-Si interaction in the interface region. Even at room temperature (300 K) strong interaction between Dy and Si atoms takes place due to charge transfer from Dy to Si. At this temperature, at the interface, a predominantly Dy-rich DysSi 3 phase is observed. Whereas at an annealing temperature of 623 K a silicon-rich DySi2 phase is observed. At an intermediate temperature of 423 K both these phases are seen with some amorphous background.