Electrophilic reactions in aromatics
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The document summarizes the general mechanism of electrophilic aromatic substitution reactions. It involves a two-step process where an electrophile first forms a covalent bond with the aromatic ring by accepting an electron pair, forming an intermediate called an arenium ion. The arenium ion then either loses a proton to form the substituted product or the proton is transferred elsewhere. Specifically, it discusses how sulphonation occurs, adding sulfuric acid to benzene via concentrated or fuming sulfuric acid, and how desulphonation can reverse this process by heating the aromatic sulfonic acid.
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Electrophilic aromatic substitution is a reaction where an atom attached to an aromatic system is replaced by an electrophile. The aromatic ring attacks the electrophile, forming a carbocation intermediate. This intermediate is stabilized by resonance. A Lewis base then donates electrons back to the ring, restoring aromaticity. Substituents can activate or deactivate the ring by donating or withdrawing electron density. Activating groups make the reaction more likely and direct substitution to the ortho- and para- positions, while deactivating groups have the opposite effects.
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I hope You all like it. I hope It is very beneficial for you all. I really thought that you all get enough knowledge from this presentation. This presentation is about materials and their classifications. After you read this presentation you knowledge is not as before.
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This is Power Point Presentation on Topic "Electrophilic Aromatic Substitution Reactions" as per syllabus of "University of Mumbai" for S.Y. B. Pharmacy (Sem.: IV) students.
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1. Electrophilic aromatic substitution is the characteristic reaction of benzene rings. A hydrogen atom is replaced by an electrophile through a two-step mechanism involving a resonance-stabilized cyclohexadienyl carbocation intermediate.
2. Substituents on benzene rings activate or deactivate the ring towards electrophilic aromatic substitution by influencing the stability of the carbocation intermediate. Electron-donating groups activate the ring while electron-withdrawing groups deactivate it.
3. The identity of existing substituents determines the orientation of new substituents, favoring either ortho/para or meta positions in electrophilic aromatic substitution.
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Benzene has 6π electrons delocalized in 6p orbitals that overlap above and below the plane of the ring. Because benzene’s six pie electrons satisfy Huckel’s rule, benzene is especially stable. Reaction that keep the aromatic ring intact are therefore favoured
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1) The document discusses electrophilic aromatic substitution reactions (EAS), where an electrophile such as a nitronium ion or halogen attacks an aromatic ring.
2) It explains how substituents on the aromatic ring can activate or deactivate the ring towards EAS through electronic effects, directing substitution to the ortho, para, or meta positions.
3) Electron donating groups activate the ring, while electron withdrawing groups deactivate it. Donating groups stabilize ortho/para intermediates, directing to those positions, while withdrawing groups direct to the meta position.
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Electrophilic aromatic substitution is a reaction where an atom attached to an aromatic system is replaced by an electrophile. The aromatic ring attacks the electrophile, forming a carbocation intermediate. This intermediate is stabilized by resonance. A Lewis base then donates electrons back to the ring, restoring aromaticity. Substituents can activate or deactivate the ring by donating or withdrawing electron density. Activating groups make the reaction more likely and direct substitution to the ortho- and para- positions, while deactivating groups have the opposite effects.
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I hope You all like it. I hope It is very beneficial for you all. I really thought that you all get enough knowledge from this presentation. This presentation is about materials and their classifications. After you read this presentation you knowledge is not as before.
Electrophilic aromatic substitution reactions
This is Power Point Presentation on Topic "Electrophilic Aromatic Substitution Reactions" as per syllabus of "University of Mumbai" for S.Y. B. Pharmacy (Sem.: IV) students.
Aromatic electrophilic substitution mishu
1. Electrophilic aromatic substitution is the characteristic reaction of benzene rings. A hydrogen atom is replaced by an electrophile through a two-step mechanism involving a resonance-stabilized cyclohexadienyl carbocation intermediate.
2. Substituents on benzene rings activate or deactivate the ring towards electrophilic aromatic substitution by influencing the stability of the carbocation intermediate. Electron-donating groups activate the ring while electron-withdrawing groups deactivate it.
3. The identity of existing substituents determines the orientation of new substituents, favoring either ortho/para or meta positions in electrophilic aromatic substitution.
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Benzene has 6π electrons delocalized in 6p orbitals that overlap above and below the plane of the ring. Because benzene’s six pie electrons satisfy Huckel’s rule, benzene is especially stable. Reaction that keep the aromatic ring intact are therefore favoured
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I hope You all like it. I hope It is very beneficial for you all. I really thought that you all get enough knowledge from this presentation. This presentation is about materials and their classifications. After you read this presentation you knowledge is not as before.
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Electrophilic substitution reactions involve an electrophile replacing a functional group, typically a hydrogen atom, on an organic compound. There are two main types: electrophilic aromatic substitutions, where the electrophile replaces an atom in an aromatic ring, and electrophilic aliphatic substitutions, where the electrophile replaces a group on an aliphatic compound. Both proceed by a three step mechanism of electrophile generation, carbocation formation, and proton removal to restore aromaticity.
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I hope You all like it. I hope It is very beneficial for you all. I really thought that you all get enough knowledge from this presentation. This presentation is about materials and their classifications. After you read this presentation you knowledge is not as before.
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- Classification of compounds based on aromaticity and examples of antiaromatic compounds.
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2) Pauling proposed that benzene's structure is better described as a hybrid involving delocalization of the p-electrons around the ring, giving it extra stability.
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Kekulé had a dream in which he envisioned snakes grasping their own tails and forming rings, inspiring his hypothesis that carbon atoms in benzene are arranged in a ring structure with alternating single and double bonds. This ring structure explains benzene's stability and resistance to addition reactions compared to open-chain alkenes. Aromatic compounds are named for many originally having pleasant aromas, though the term now refers to chemical stability conferred by conjugated planar ring structures like benzene that allow for resonance. These compounds are important industrially as precursors to dyes, drugs, polymers, and other chemicals.
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The document discusses aromatic electrophilic substitution reactions including the Vilsmeier-Haack formylation, Reimer-Tiemann reaction, Gattermann-Koch formylation, and diazo coupling reactions. It provides background on the reactions, their mechanisms, substrates used, and factors that influence product distribution. Examples and problems are also given to illustrate the application of these reactions in synthesis.
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In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula CₙH₂ₙ−2
Chapter 3 Alkenes and Alkynes
This document provides an overview of alkenes and alkynes reactions. It discusses addition reactions of alkenes including hydrohalogenation, hydration, halogenation, hydrogenation, oxidation, and polymerization. It also covers conjugated dienes, the Diels-Alder reaction, and drawing resonance forms. For alkynes, the document discusses reduction, addition reactions, hydration, oxidative cleavage, acidity, and acetylide anion formation and reactions.
Benzene &; its derivative
Introduction to benzene, orbital picture, resonance in benzene, Huckel‟s rule
Reactions of benzene - nitration, sulphonation, halogenation- reactivity, Friedel- Craft‟s alkylation- reactivity, limitations, Friedel-Craft‟s acylation.
Substituents, effect of substituents on reactivity and orientation of mono substituted benzene compounds towards electrophilic substitution reaction.
Alkanes
Alkanes are saturated hydrocarbons that contain only carbon and hydrogen. They have the general formula CnH2n+2 and contain single bonds between carbon atoms. Alkanes are highly stable due to weak polarization of carbon-hydrogen bonds. They undergo substitution reactions and reactions at high temperatures like halogenation and cracking. Alkanes can be synthesized by hydrogenation of alkenes/alkynes, reduction of alkyl halides, and Wurtz reaction.
Name Reactions part 1 sem iv poc iii
Name Reactions of synthetic importance
Pinacol-Pinacolone, Hofmann, Baeyer-Villiger oxidation, Benzilic acid rearrangement
reaction, Beckmann’s rearrangement and Schmidt rearrangement
Benzene
Benzene is a colorless liquid with a sweet odor that is found naturally in crude oil and gasoline. Michael Faraday first isolated benzene in 1825 from illuminating gas. Benzene's stability is due to its resonance structure containing alternating single and double bonds. The main electrophilic aromatic substitution reactions of benzene are halogenation, nitration, sulfonation, and Friedel-Crafts acylation and alkylation. Activating groups like -OH increase the rate of substitution at the ortho and para positions by increasing electron density on the ring, while deactivating groups like -NO2 direct substitution to the meta position. Alkylbenzene side chains can undergo halogenation and
Electrophilic substitution reaction
This document discusses the molecular orbital diagram of benzene and electrophilic substitution reactions. It describes how benzene has delocalized pi molecular orbitals formed from the unhybridized p orbitals of each carbon atom. Nitration and halogenation are given as examples of electrophilic substitution reactions, where an electrophile such as the nitronium ion or chloronium ion attacks the benzene ring. The mechanisms of these reactions involve the formation of an electrophile, then a sigma complex intermediate, followed by formation of the final substituted product. Friedel-Crafts reactions like alkylation and acylation are also discussed as types of electrophilic substitutions catalyzed by Lewis acids.
Common named reactions
The document discusses several carbon-carbon bond forming reactions:
1. Aldol condensation allows aldehydes and ketones to undergo self-condensation in the presence of a base to form β-hydroxy carbonyl compounds.
2. The Perkin reaction uses an acid anhydride to form α,β-unsaturated aromatic acids from aromatic aldehydes.
3. The Wittig reaction converts a carbonyl group to an alkene using a phosphonium ylide.
Introduction to Organic Chemistry.pdf
The document discusses electrophilic addition reactions of alkenes. It introduces the topic and provides details about reaction mechanisms and kinetics. Specifically, it explains that (1) alkenes undergo addition reactions where an electrophile attacks the carbon-carbon double bond, (2) the reaction follows a two-step mechanism where the double bond first attacks the electrophile to form a carbocation intermediate which is then attacked by a halide ion, and (3) reaction rates increase with increasing alkyl substituents on the alkene and decreasing hydrogen-halogen bond strength as it stabilizes the carbocation intermediate.
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The document discusses several biogeochemical cycles including the water, carbon, nitrogen, phosphorus, and sulfur cycles. It provides details on the reservoirs, assimilation, and release stages of each cycle. For example, it notes that the water cycle involves evaporation and precipitation moving water between oceans, air, groundwater, lakes, and glaciers. Plants absorb water from the ground and animals drink or eat plants, while transpiration and excretion release water back. The carbon cycle describes photosynthesis fixing carbon from the air and respiration releasing it, and the nitrogen cycle involves nitrogen fixation, nitrification, and denitrification moving nitrogen between air, soil, plants, and animals.
Transplants , eugenics and their issues
Transplants and eugenics raise complex ethical issues. Transplants require lifelong immunosuppressant drugs and organ shortages remain an issue. Eugenics aims to improve genetics but has been discredited due to flawed science and links to atrocities. While genetic screening now focuses on counseling rather than control, debates continue on prenatal testing, genetic engineering, and enhancing traits.
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Nucleic acid-and-cell-based-therapies
Nucleic acid and cell based therapies involve gene therapy and cell therapy. Gene therapy aims to introduce new genes into cells to treat genetic diseases by replacing defective genes. Early gene therapy trials focused on ex vivo and in vivo approaches. Viral vectors like retroviruses were primarily used but posed safety risks. Non-viral methods using naked DNA or vectors like liposomes were developed. Diseases targeted include cancer, genetic disorders, and AIDS. Antisense oligonucleotides can bind mRNA and inhibit gene expression. RNA interference uses short interfering RNAs to induce sequence-specific gene silencing. Ribozymes and aptamers also provide nucleic acid based therapeutic approaches.
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DNA sequencing involves determining the order of nucleotides in a DNA molecule. There are several methods for DNA sequencing, including Sanger sequencing using chain termination with dideoxynucleotides, Maxam-Gilbert chemical sequencing, shotgun sequencing by fragmenting DNA into random pieces, and newer next-generation sequencing technologies like Illumina sequencing and Ion Torrent sequencing that are faster and cheaper. Understanding DNA sequences can provide insight into genetic conditions and diseases and has applications in medicine, agriculture, and forensics.
Basics of DNA & RNA (Nucleic acid)
DNA sequencing involves analyzing the order of nucleotides in DNA. There are two types of nucleic acids: DNA and RNA. DNA is found in the nucleus and the amount is constant in somatic cells but half in gametes. Nucleotides are the subunits of DNA and RNA and contain a phosphate group, a sugar (ribose or deoxyribose), and a nitrogenous base. A nucleoside contains a sugar and base while a nucleotide additionally contains a phosphate group. The structures of nucleotides involve the phosphate group bonding to the sugar, the sugar-phosphate backbone formed by phosphodiester linkages between sugars, and various nitrogenous bases including purines and pyrimidines bonding to the sugar.
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Evaporation & crystalization
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Drying process
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Chromatography
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Centrifuges use centrifugal force generated by high-speed rotation to separate solids from liquids. There are several types of centrifuges including sedimentation units, filtration units, tubular-bowl centrifuges, continuous decanter centrifuges, self-opening centrifuges, multi-chamber centrifuges, and disk centrifuges. Centrifuges are used widely in industries such as food processing, pharmaceuticals, chemicals and ethanol production to separate and purify mixtures.
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Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
原版制作(carleton毕业证书)卡尔顿大学毕业证硕士文凭原版一模一样
原版纸张【微信：741003700 】【(carleton毕业证书)卡尔顿大学毕业证】【微信：741003700 】学位证，留信认证（真实可查，永久存档）offer、雅思、外壳等材料/诚信可靠,可直接看成品样本，帮您解决无法毕业带来的各种难题！外壳，原版制作，诚信可靠，可直接看成品样本。行业标杆！精益求精，诚心合作，真诚制作！多年品质 ,按需精细制作，24小时接单,全套进口原装设备。十五年致力于帮助留学生解决难题，包您满意。
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3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
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When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
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4:这个认证书并且可以归档倒地方
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Presented at June 6-7 Texas Alliance of Groundwater Districts Business MeetingDeep Software Variability and Frictionless Reproducibility
Deep Software Variability and Frictionless ReproducibilityUniversity of Rennes, INSA Rennes, Inria/IRISA, CNRS
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
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With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
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Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
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Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
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ESR spectroscopy in liquid food and beverages.pptx
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Electrophilic reactions in aromatics
- 1. General Mechanism Of Electrophilic aromatic Substitution reaction 1
- 2. Allows the formation of covalent bond Bond between aromatic cycle and electrophile By transferring on electron pair from aromatic compound. Two step mechanism: Add of electrophile in the aromatic nucleus result in the formation of intermediate and called an arenium ion 2
- 3. 1. 2. According to lewis concept Y is base because it donates electron 3
- 4. Sulphonation Sulphuric acid is incorporated in benzene ring by two method. Conc. Sulphuric acid at 80c Fuming Sulphuric acid at room temperature 4
- 5. 5
- 7. 7 When an aromatic sulfonic acid is heated to 100- 175c with aqueous acid. It is converted into sulfuric acid and an aromatic H/C. This desulfonation is the exact reverse of the sulfonation processed by which the sulfuric acid was originally made.