الفهرس 
Synthesis of ?-aminophosphonates via Arbuzov reactionOnly 14 pages are availabe for public view
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Abstract
Organophosphorus compounds especially, α-aminophosphonic acids (I) and their
esters (II), have a potential biological activity due to the similarity with α-amino acids
(III). They represent an essential analogy to α-amino acids (III) as we replaced a
carboxylic group with a phosphonic acid ester moiety (cf. scheme. 1). The preparation of
new analogs and development of an efficient synthetic procedure is one urgently
important in the field of organophosphorus chemistry.
In this context, a method of synthesizing α-aminophosphonates has been developed
to improve their achievability and scalability. In continuation of our previous efforts to
develop a suitable strategy to synthesize and enhance the scalability of organophosphorus
compounds to be used in different biological and environmental applications.
The first chapter is the introduction: which gives an overview of Corrosion and
was also reviewed in terms of definition, causes, types, and how to protect against it using
various inhibitors, including α-aminophosphonates compounds. also, the chemistry of α-
aminophosphonates including synthesis, reactions, and environmental application as
corrosion inhibitors were reported.
The second chapter discussed the design and synthetic strategies used to obtain α-
aminophosphonates. This chapter also includes the screening results of their
environmental application as anticorrosion inhibitors for different metals such as carbon
steel, copper, and zinc in different corrosive media acidic (hydrochloric acid and sulfuric
acid) or alkaline medium (potassium hydroxide). Corrosion inhibition properties of α-aminophosphonates were studied with different roughness levels using potentiodynamic
polarization, electrochemical impedance, and weight loss measurement
The third chapter presented all the experimental procedures used in the
development of the current study. Synthetic methodology, physical-chemical properties,
and environmental applications study.
Various spectroscopic methods such as IR, 1H-NMR, 13C-NMR, 31P-NMR, BET, and
SEM-EDX microanalysis were used to elucidate the expected structure of the synthesized
compounds. Such characterization data showed analytical results consistence with their
proposed structure. (c.f. The experimental part for more details).
The following is the main summary of the thesis results:
1. Model system for a one-pot synthesis of α-aminophosphonate (4a-4c)
The one-put reaction of the equimolar ratio of an aldehyde with amine,
triphenylphosphite, and (10-mole percent) of LiClO4 in acetonitrile at room temperature,
afforded α-aminophosphonates 4 in a good yield and high purity as depicted in Scheme 2. Application part
1. corrosion inhibitor for carbon steel in acidic solutions
α-aminophosphonate (4a) is used as a novel corrosion inhibitor for carbon steel.
The aggressive media applied in this study are HCl and H2SO4 acid solutions. The
findings indicate that the morphology of compound 4a is cubic, with particles ranging in
size from 17 to 33 μm. FT-IR, 1HNMR, 31PNMR, and 13CNMR analysis confirmed the
synthesis of the 4a molecule. It has been discovered that compound 4a plays an important
role in inhibiting the corrosion of carbon steel in both HCl and H2SO4 acids. This was
identifiably inferred from the fact that the addition of the compound 4a decreased the
corrosion rate. It is important to report that the maximum inhibition efficiency
potentiodynamic polarization (pp) (92.4% for HCl and 95.7% for H2SO4) was obtained
at 180 ppm. The primary factor affecting the rate at which steel specimens corrode in
acidic electrolytes is the tendency of α-aminophosphonates compounds to adsorb on the
surface of steel through their hetero-atoms (O, N, and P). This was verified by SEM/EDX
results. The adsorption occurs through physical and chemical mechanisms via different
active centers which are matched with the calculated quantum parameters.
The Langmuir isotherm provided the best fit. Straight lines were drawn from the
figure, and regression coefficients (R2) nearly equal to unity confirm that the data suited
to Langmuir adsorption isotherm well. For HCl and H2SO4 solutions, the values of Kads
determined from the Langmuir adsorption isotherm are (2642.6 and 5285.2) M-1,
respectively. the computed average ΔGads values are -29.5 and -31.2 kJ mol-1,
respectively. This implies the existence of both physisorption and chemisorption
mechanisms. Furthermore, theoretical calculations using DFT are applied to illustrate the
relation between the electronic structure and the corrosion behavior of 4a.
2. Corrosion inhibitor for copper in acidic solutions
A new corrosion inhibitor for copper in acidic media is (4b). The aggressive
mediums used in this investigation are acid solutions of HCl and H2SO4. Analysis using
the FT-IR, 1HNMR, 31PNMR, 13CNMR, and BET confirmed that the molecule of 4b was successfully synthesized. The anti-corrosion capabilities of 4b are evaluated using a
combination of chemical, electrochemical, and quantum studies. The substance 4b is
crucial in preventing the corrosion of copper in both HCl and H2SO4 acid. This was
implied by the observation that the corrosion rate decreased when (4b) was added. It is
significant to note that 180 ppm produced the highest levels of inhibiting efficiency from
pp (96.2% for HCl and 92.6% for H2SO4). Results from SEM/EDX tests supported this. The
actual adsorption takes place via various active centers (nitro, phosphonate, and methoxy
groups).
Thermodynamic studies by Arrhenius plot and Eyring–Polanyi plot show that the
activation energy Ea of copper corrosion in HCl and H2SO4 solutions with (4b) inhibitor
is greater than that of the control solution. Increased 4b inhibitor molecule adsorption on
the metal surface could explain the rise in the apparent activation energy for copper
corrosion in inhibited acid solutions. the values for Ha are higher in the presence of the
inhibitor than they are in the uninhibited solution. This implies that the energy required
for copper to dissolve in acidic solutions increases when a 4b inhibitor is present. This
indicates that it is challenging to dissolve copper in acid solutions when (4b) inhibitor is
present.
The Langmuir isotherm. Regression coefficients (R2) are practically equal to unity
and the ability to draw straight lines from the graphic demonstrates how well the data fit
the Langmuir adsorption isotherm. The values of Kads derived using the Langmuir
adsorption isotherm for HCl and H2SO4 solutions (13184 M-1) and (9064 M-1),
respectively. A high Kads value indicates higher 4b adsorption. For solutions of HCl and
H2SO4, the computed average ΔGads values are -33.4 and -32.5 kJ mol-1, respectively. This
implies the existence of both physisorption and chemisorption mechanisms. The negative
values of ΔGads for the 4b inhibitor’s adsorption on copper reflect the stability and
spontaneity of adsorption processes 3. inhibitor for zinc electrode in zinc alkaline batteries
Using (4c) A new corrosion inhibitor for zinc in alkaline batteries. The aggressive
mediums used in this investigation are alkaline solutions of KOH (5M). FT-IR, 1H NMR, 31P
NMR, 13C NMR, and BET studies were used to differentiate the successfully produced α-
aminophosphonates. based on the findings. It has been discovered that the inhibitor significantly
reduces zinc corrosion in KOH solution. The finding that the addition of zinc inhibitor greatly
decreased the rate of corrosion strongly suggested this. At 350 ppm, the highest level of inhibition
(96.2%) was produced from weight loss measurements. The adsorption of the inhibitor is
categorized in great depth using the Langmuir adsorption isotherm. the presence of (4c) inhibitor
enhances the capacity of the battery.
Thermodynamic studies by Arrhenius plot and Eyring–Polanyi plot, the information
demonstrates that the values for Ha are higher in the presence of the inhibitor than they are in the
uninhibited solution. This implies that the energy required for zinc to dissolve in an alkaline
solution increases when an inhibitor is present. This indicates that it is challenging to dissolve
zinc in an alkaline solution when the inhibitor is present.
The Langmuir isotherm straight-line relationship was obtained with a correlation
coefficient (R2) of 0.9856. Also, the values of Kads derived for the KOH solution (17591 M-1). A
high Kads value indicates higher inhibitor adsorption on the surface of zinc. the computed average
Gads value is 32.26 kJ mol-1. This implies the existence of both physisorption and chemisorption
mechanisms. The negative ΔG°
ads value is consistent with the spontaneity of the adsorption
process and the stability of the adsorbed layer on the Zn surface.