This work involves the synthesis and characterization of asymmetrical pyromellitdiimide
derivatives [IV]a-f
by four sequence steps selective reaction . One mole of pyromellitic dianhydride
was reacted with one mole of various primary aromatic amines [ 4-nitro aniline , 4-chloro aniline , 4-toludine and 4-anisidine] in excess of dry acetone to produce six compounds (N-substituted-pyromellitamic monoacid) [I]a-f . These new compounds [I]a-d were converted to the corresponding
N- substituted- pyromellitmonoimide [II]a-d via their heating at (80-90)
0
C in sodium acetate-acetic
anhydride mixture .
The compounds [II]a-f
were allowed to react with one mole of another primary amines in
excess of dry acetone to give new derivatives of amic acid [II]a-d followed by intramolecular
cyclization reaction of these compounds [IV]a-f in sodium acetate-acetic anhydride system to yield the
desired asymmetrical pyromellitdiimide derivatives [IV]a-f
, the above reactions can be summarized in
Scheme 1.
All the synthesized compounds have been studied and charachterized by their melting points
, FTIR , and
1
HNMR spectroscopy (for some of them)
Let be a connected graph with vertices set and edges set . The ordinary distance between any two vertices of is a mapping from into a nonnegative integer number such that is the length of a shortest path. The maximum distance between two subsets and of is the maximum distance between any two vertices and such that belong to and belong to . In this paper, we take a special case of maximum distance when consists of one vertex and consists of vertices, . This distance is defined by: where is the order of a graph .
In this paper, we defined – polynomials based on
... Show MoreThe research aims at:
- Identifying the problems facing kindergarten teachers.
- Identifying the nature of the problems facing kindergarten teachers.
To achieve the aim of the research, the researcher prepared a questionnaire to identify the problems that face the teachers of kindergartens. The questionnaire was subjected to the consultation of a group of specialized expertise in the educational and psychological sciences to certify the propriety of the items of the questionnaire and it gained a rate of (80%), and the stability of the scale gained (0.91) and it stands for a correlation parameter with a statistical significance and it was calculated by using Person’s R Corre
... Show MoreBackground:
بحث لمعرفة رواة السنن والمسانيد للحافظ ابن نقطة
International attention to the fight against the financing of terrorism has been one of the most important systemic transformations of the modern international strategy for the prevention of the crime of terrorism. International attention to the financing of terrorism has gone through multiple periods، considering that funding has not been a priority for the international community. Which led the international community to notice that there are tools that assist terrorists, the most important of which is the financial instrument, namely finance. This has led the Security Council، the General Assembly of the United Nations and regional organizations to issue binding decisions and to develop international conventions that would And to ma
... Show MoreThe research aims to identify the level of Agentic thinking among a sample of male and female undergraduate students for both disciplines (scientific, and humanities). The researcher targeted the third and fourth stages for the academic year
(2021-2022). The study sample is (382) male and female students who were selected randomly from the University of Baghdad. To achieve the above-mentioned study aims. The researcher has developed a scale of Agentic thinking consisting of (25) items distributed over three domains. The results showed that the study sample has a high level of Agentic thinking. There are significant differences in agentive thinking in terms of gender in favor of females. There are no statistically significant diff
... Show MoreUnsaturated polyester toughened Epoxy was developed. Epoxy resin had toughened by weight fraction of 10, 20, 30, and 40 wt. % unsaturated polyester. FTIR spectroscopy has been used to investigating the intermolecular hydrogen bonding. Unsaturated polyester–epoxy matrices were characterized for their thermal properties. The FTIR test detected a peak shift of the functional groups which can explain cross-linking occurs between the two resins. The crosslinking between epoxy and unsaturated polyester confirmed via the existence of the stretching asymmetrical C-C band and contraction of the C-O band. The DSC test demonstrated that glass transition temperature value decreases with epoxy strengthening. The specific heat capacity and the
... Show MoreThe ion tail temperature of the comet ISON was calculated by using magneto-hydrodynamic MHD laws. From these equations the focus is concentrating on determine the ion tail temperature from the relations of dynamic and static pressures results.MHD equations are numerically solved using Matlab simulation code using cubic volume element method, based on three dimensionl Cartesian coordinates that devided into equal 15x15x15 equally spaced mesh. The simulation was performed using 3-D Lax explicit method considering normalised physical propreties relative to those of the solar wind at 1 AU. The results explained that it is possible to deduce two types of temperature, the first being the isotropic temperature which is shown to vary slowly with
... Show MoreThe Asphalt cement is produced as a by-product from the oil industry; the asphalt must practice further processing to control the percentage of its different ingredients so that it will be suitable for paving process. The objective of this work is to prepare different types of modified Asphalt cement using locally available additives, and subjecting the prepared modified Asphalt cement to testing procedures usually adopted for Asphalt cement, and compare the test results with the specification requirements for the modified Asphalt cement to fulfill the paving process requirements. An attempt was made to prepare the modified Asphalt cement for pavement construction in the laboratory by digesting each of the two penetration grade Asphalt c
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