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Substitution reaction

Introduction Substitution reaction of chemistry substitution reaction are also called displacement reactions .These are the reactions in which an atom or a group of atoms attached to a carbon atom in a molecule is replaced by some other atom or group of atoms without any change in the structure of the remaining part of the molecule. The product formed is known as the substitution product. The new atom or group which enters the molecule is called the substituent. Some example of substitution reactions are: CH₄ cl₂ → CH₃cl Hcl Methane Methyl chloride Here H-atom of CH₄ is replaced by chloride atom. CH₃-CH₂Br KOH (aq) → CH₃CH₂OH KBr Ethyl bromide Ethyl alcohol Here Br atom of ethyl bromide is replaced by OH group. CH₃ -CH₂ = CH₂ → ClCH₂ -CH=CH₂ Hcl Propene Allyl chloride Here H-atom of CH₃ group is replaced by cl-atom Types of substitution reaction Depending upon the nature of attacking reagent, substitution reactions can be classified as below: a) Electrophilic Substitution Reactions : – These are the reactions in which an atom or group in a molecule is replaced by an electrophile. Such reactions are shown by aromatic compound. CH₅ HONO₂→ CH₅NO₂ H ₂0 CH₅ NO₂→CH₅ NO₂ H ₂0 (H ₂s0 ₄) Here Nitronium ion (NO₂ ions )acts as an electrophile and the process is called nitration. Mechanism. Consider the chlorination of benzene in presence of halogen carrier(Fecl₃) Fecl₃ cl-cl → Fecl₄⁻ cl(chloronium ion) Electrophiles are involved in electrophilic substitution reactions and particularly in electrophilic aromatic substitutions: Electrophilic reactions to other unsaturated compounds than arenes generally lead to electrophilic addition rather than substitution. B) Necleophilic Substitution Reactions:- These are the reaction sin which an atom or a group in a molecule is replaced by a nuclophile. Such reactions are shown by alkyl halides. Consider the action of aqueous KOH on methyl chloride. HO⁻ H -CH₃ Cl→ Ho-cH₃OH cl⁻ A nucleophile (literally “nucleus lover”) is a molecule or ion capable of acting as a Lewis base (i.e., an electron pair donor). Nucleophiles can be described as “electron-rich” while their targets or substrates can be described as “electron-deficient” (they are Lewis acids, i.e., electron pair acceptors). In a nucleophilic substitution the nucleophile takes the place of–or substitutes for–some atom or group on the substrate (called the “leaving group”): Nu: R:L → R:Nu :L- nucleophile substrate product leaving group If the nucleophile is neutral (as shown above) the product will be charged since the leaving group takes both bonding electrons away with it. If the nucleophile is an anion then the product will be neutral: Nu: – R:L → R:Nu :L- Stronger bases make better nucleophiles (e.g., OH- is a better nucleophile than H2O). “Good” substrates include cations, central atoms with incomplete octets or double bonds (like sp2 carbons) or carbons with partial positive charges. Halogens are generally more electronegative than carbon and so organohalogen compounds are usually subject to nucleophilic attack at the carbon attached to the halogen (which would be the positive end of a dipole). For example, 2-chloro-2-methylpropane (commonly known as t-butyl chloride) will undergo nucleophilic substitution with hydroxide ion: (CH3)3CCl OH – → (CH3)3COH Cl – This is a typical synthetic route for producing an alcohol from an alkyl halide. Nucleophilic substitution reactions have been studied for many years. It was noticed fairly early that while the overall reaction was similar in the vast majority of cases the kinetics of the process was not always the same. In some substitutions the concentration of the nucleophile had no effect on the rate. In others, the rate was directly proportional to the concentration of the nucleophile. This suggested that two different mechanisms must be at work. The factor which determines the mechanism employed is typically the nature of the substrate itself and NOT the particular nucleophile. Necleophilic substitution reactions are further classified as:- 1)Necleophilic substitution Biomolecular :- Such reaction sare shown by primary alkyl halides and involve a single step. The breaking of C-X bond and the making of C-OH bond takes place simultaneously. The neucleophile approaches the C-atom from the side opposite to that carrying the halogen. In such reactions, an inverted product is formed. The reaction involves the formation of a transition state. The reaction follows the rate law, Rate=k[Alkyl halide][OH]. As the slow rate determining step involves two molecule(Alkyl halide and alkali); therefore, the reaction is known as bimolecular substitution reaction. Most necleophilic substitutions, which involve the expulsion of an originally neutral substituent ,notably of halogen, from the aromatic ring,at temperature which are not particularly high,use the biomolecular mechanism SN2. This is established by their second order kinetics, which are documented by many records, (NO₂)₂CH₃•Cl OEt⁻→(NO₂)₂CH₃•OEt Cl⁻ In substitution of this type,the rate of attack by different reagent on the same aromatic molecules follow the general order of nucleophilic strength towards carbon. This is the conclusion to which Bunnatt and Zahler come after having assembled data from many sources. The first mechanism is known as SN1 (substitution, nucleophilic, unimolecular) because only one molecule is involved in the first step–the rate determining step. Reactions occurring by this mechanism should exhibit first-order kinetics, i.e., the rate law should have the form “rate = k[substrate]1”. Because the nucleophile is not involved until after the slow step its concentration will have no effect on the rate. The alternate mechanism is called SN2 (substitution, nucleophilic, bimolecular) because two molecules are involved in the rate determining (and only) step. Such reactions exhibit overall second-order kinetics. The rate is proportional to both the concentration of the substrate and the concentration of the nucleophile. Reactions like this will have a rate law in the form “rate = k[substrate] [nucleophile] 2) Nucleophilic Substitution Unimolecular:- This mechanism is generally followed by tertiary alkyl halide. In the first step, tertiary alkyl halie breaks hydrolytically to form intermediate carbonium ion. The formation of carbonium ion is the slow rate determing step. In the second step, the nucleophile attacks tha carbonium ion to form an alcohol. Consider the action of aqueous KOH or tertiary Butyl bromide. CH₃ CH₃ CH₃ ____ C—-Br ⇄ CH₃ ——C Br⁻ (Slow Step) CH₃ CH₃ CH₃ CH₃ CH₃ ____ C OH⁻ ⇄ CH₃ ——C OH (Fast Step) CH₃ CH₃ (carbonium ion) Tert. butyl alcohol Or The best established eample of nucleophilic aromatic substitution by the unimolecular mechanism ,SN1,is the uncatalysed decomposition of diazoium ions,in hydroxylic solvent,to give phenols or phhenolic ethers,accomplished often byaryl halides or others such substitution products, if the necessary necleophilic anions are present in the solution: ArN₂ → Ar N₂ (Slow) Ar H₂o →Ar• OH H (fast) Ar ROH→Ar•OR H (Fast) Ar cl ⁻→ Ar• Cl (Fast) These are SN1 mechanism . The alternate mechanism is called SN2 (substitution, nucleophilic, bimolecular) because two molecules are involved in the rate determining (and only) step. Such reactions exhibit overall second-order kinetics. The rate is proportional to both the concentration of the substrate and the concentration of the nucleophile. Reactions like this will have a rate law in the form “rate = k[substrate] [nucleophile] 3) Free Radicals Subsitution Reactions[1.2.3] These are the reactions in which an atom or group of atoms in a molecule is replaced by a free radical. The replacement of H- atom by a halogen atom is an example of free radicals substitution.In the free radical substitution reaction, the attacking reagent is a free radicals. These reactions are carried either at high temperature or in the presence of ultra-violet light. In organic chemistry, a radical substitution reaction is a substitution reaction involving free radicals as a reactive intermediate The reaction always involves at least two steps, and possibly a third. In the first step called initiation (2,3) a free radical is created by photolysis. Homolysis can be brought about by heat or light but also by radical initiators such as organic peroxides or azo compounds. Light is used to create two free radicals from one diatomic species. The final step is called termination (6,7) in which the radical recombines with another radical species. If the reaction is not terminated, but instead the radical group(s) go on to react further, the steps where new radicals are formed and then react is collectively known as propagation (4,5) because a new radical is created available for secondary reactions. Mechanism. The mechanism of free radicals substitution involves three steps:- I) Initiation :- In this step, halogen molecule breaks homolyticallly to form free radicals. Consider the action of Br₂ on ethane in presence of sunlight. Br-Br Br II) Propagation step:— The Br formed in the first step reacts with alkane molecule to form new free radicals which in turn reacts with bromine molecule and the chain react ion starts and so on. CH₃CH₃ Br →CH₃ CH₂ HBr CH₃ CH₂ Br -Br →CH₃ CH₂Br Br 3) Termination.:— In this step, the free radicals combine and the reaction stops. Br Br → Br₂ Similarly, consider action of Cl₂ on propene. I) cl – cl→ 2Cl II) CH₂=CH- CH₃ Cl→ CH₂=CH- CH₂ HCl CH₂=CH- CH₂ Cl-Cl→ CH₂=CH-CH₂Cl Cl Substitution Reactions[1.2.3] Substitution Reactions. In an acid-base reaction such as CH3CO2H NH3 → CH3CO2 – NH4 the N acts as a nucleophile (Greek for “loving the nucleus), the H acts as an electrophile (“loves electrons”), and the O that accepts the pair of electrons acts as a leaving group. The acid-base reaction is the simplest model for a substitution reaction, which is a reaction in which a σ bond between atom 1 and atom 2 is replaced by a σ bond between atom 1 and atom 3. Substitution reactions are incredibly important in organic chemistry, and the most important of these involve substitutions at C. For example: This substitution reaction, discovered in 1849, involves the nucleophilic O making a new bond to the electrophilic C, and the bond between the electrophilic C and the leaving group I breaking. Any Brønsted base can also act as a nucleophile, and any nucleophile can also act as a Brønsted base, but some compounds are particularly good bases and particularly poor nucleophiles, whereas some are particularly poor bases and particularly good nucleophiles. Any Brønsted or Lewis acid can also act as an electrophile, but there are many electrophiles that are neither Brønsted nor Lewis acids (as in the example above). A haloalkane, e.g. CH3CH2Br, can in principle undergo either of two polar reactions when it encounters a lone pair nucleophile, e.g. MeO-. First, MeO- might replace Br- at the electrophilic C atom, forming a new C-O bond and giving an ether as the product. This is substitution, because the C-Br σ bond is replaced with a C-O σ bond. Second, MeO- might attack a H atom that is adjacent to the electrophilic C atom, giving MeOH, Br-, and an alkene as products. The electrons in the C-H bond move to form the π bond, and the electrons in the C-X bond leave with X-. This is elimination, because a new π bond is formed, and because the elements of the organic starting material are now divided between more than one product. Elimination requires that the substrate have a C-X bond and adjacent C-H bonds, while substitution requires only that the substrate have a C-X bond. Nucleophilic aromatic substitution reaction The name in the title in given to those substitution in whichnucleophilic reagent, such as Br⁻, combine with aromatic carbon and aprecltyuviously present substituent such as •Cl,•NO₂, becomes expelled along with its bonding electrons With considerable difficultly even •H may be expelled with its bonding electrons i.e at H⁻. Biomolecular substitution reaction electron attracting substituent especially one conjugated with aromatic system such as nitro,carbonyl,syano aids the attack of the reagent and a 2-or 4-situated hetero atom ,as n pyridine ,acts in a similar way. Neuclophilic aromatic substtion can proceed by several,mechanism. The Unimolecular and Biomolecular mechanism can definitely be recognized and other mechanism some of which are understood,can be seen to exist. The unimolecular mechanism is limited to the replacement of those substituents which are sufficiently loosely bound to undergo spontaneous heterlysis in solution. The biomolecular mechanism is muc more general, doubtless because it make much less severe demands on thequality of the explled group,so that a hydrogen shift involved.
Capella University Network Reconfiguration Paper.

Write 1000 wordsYou have been tasked with reconfiguring the network for your company, which has grown considerably over the past year. You have used only static routing in the past, but you do not wish to spend the administrative time required to maintain the routing tables now that the network has grown. You have recently experienced numerous inaccuracies in the routing table caused by entries you made when in a hurry.Criteria for the reconfiguration includes the following:You would like to automate the entry and updating of routing information, but you are concerned about excessive memory and processor utilization if you implement dynamic routing protocols.You also wish to minimize the use of network bandwidth.You prefer that the most efficient use of bandwidth be made so that packets will travel to their destination over the truly shortest path, rather than just the path with the lowest number of hops.You have heard that routing loops can be a problem and wish to avoid them. However, you are concerned that if a link goes down, there should be redundancy so that traffic will go through.In 4 page summary, complete the followingHow can you accomplish your objectives?What routing protocols and protocol features will you use to do so?Provide detailed examples.Write a paper using the APA style that summarizes your findings, and provides enough detail to fully support your opinion.
Capella University Network Reconfiguration Paper

Lake Tahoe has not only transformed America, it has also played a major role in the conquest of California. The lake put a beginning to a sexual revolution, was a premise for a ski industry and also led to the launch of Republican Party. The novel Tahoe beneath the Surface by Scott Lankford tells about a hidden history of the most famous residents of the Lake Tahoe. The novel provides tales about Rat Pack, Mafia dons and mysterious legends of Indian tribes. The novel brings to light the values of Lake Tahoe illustrating why it is one of the hot spots in America. It also traces the steps of authors like Maxine Hong Kingston, Bertrand Russell and Michael Ondaatje. In addition, it reveals the darkest pages of the American history, such as Kennedy assassination and anti-Chinese racism. The novel also shows how lives of such famous people like Frank Sinatra, John Muir, and Mark Twain were influenced by this lake. These characters both have specific reasons as to why they value Lake Tahoe, for example Sinatra value lake Tahoe because of its glamour and glitz, while Muir values it for its natural beauty and Cousteau values the lake for its natural waters (Scott 98). However, even regardless of the influence on life of many people, there are several environmental threats that the lake faces making it increasingly vulnerable. There are also Tahoe Blue in the lake, which is a term used by the author Lankford to describe the meaning represented by the lake, its beauty and range of life around it. It is however important to preserve Lake Tahoe since it has transformed America and the people leaving around it. Lake Tahoe has acted as one of the most beautiful cites in the whole world, however, it is still troubled by numerous environmental harms. Since 1844 when Lake Tahoe was discovered, the lake has acted as scenic attraction site because of its natural beauty and surrounding which is one of the reasons why John Muir, a character in the novel, valued the lake. On the other hand, Frank Sinatra who is one of the characters in the novel, also valued the lake because of its glamour and glitz. This is one of the reasons why Lake Tahoe needs to be preserved, as its site can act as a source of revenue to America when tourists come to view the place. Many scientists, community leaders and government seek to find ways to preserve the lake and restore its distinctive biological diversity. Cousteau who is one of the characters of the novel Tahoe beneath the Surface values the Lake Tahoe for its natural waters. Lake Tahoe straddling along the California-Nevada border is well known for its clean waters usually referred to as jewel of the Sierra (Scott 100). Get your 100% original paper on any topic done in as little as 3 hours Learn More However, subsequent development and growth has become one of threats faced by Lake Tahoe since it menaces the clarity of the natural waters. This part of the lake is the centerpiece of ecosystem where many resource managers and scientists have continually been examined. They measure, sample, test and restore the biodiversity and landscape of the lake. They try their best to ensure that Lake Tahoe restores back its natural waters which has acted as a home for many plant species and wildlife. If the water is endangered then it means that the lives of these plants and animals are in danger too. This is why it is very crucial that the lake be preserved to save the plants and animals and also the clarity of the water. About 200,000 acres of the lake have ecologically sensitive slopes, marshes and meadows (Dylan 110). Economic development and growth have a negative effect on the environment of the lake despite the fact that it has contributed to the prosperity of the region that is situated near the lake. Nevertheless, there is a great decline in biodiversity in the lake due to the polluted air and soil. The soil and air around Lake Tahoe need to be fresh to enable survival of living organisms in it and around it. It is therefore crucial to preserve the lake. Regional goals have been adopted by American government to promote and expand bio-logical diversity of wildlife, fish and communities that habit in and around Lake Tahoe. Landowners around Lake Tahoe have also taken the initiative of reclaiming those parts of the lake that are troubled to see in it that they are well preserved. 85 percent of the land along Lake Tahoe belongs to California Department of Parks and Recreation, U.S Forest Service, California Tahoe Conservancy and Neva da Division of States Parks. However, the remaining part of the land along Lake Tahoe is privately owned (Byron
Walden University Asynchronous Paper.

Watch DBT Video Check: DBT as an evidence-based approachDescribe how to apply dialectics as a treatment frameworkDemonstrate through no more than two paragraphs.Students will pair up to record a role play using CBT. One student will role play a client and the other will be the therapist. They students will them switch roles. Each role play will be 20 minutes in length.Knowledge check will be instructor and GA reviewing portions of each videoWatch video of Prolonged Exposure: check:Reaction paper of no more than two paragraphs explaining the process of imaginal exposure and personal reflections on the video.Students will watch video of Motivational Interviewing: no more than two paragraphs, explain how Motivational Interviewing could be seen as a cognitive behavioral intervention.Watch video: check : In a one page paper, discuss your reactions to the way the therapist applies cognitive behavioral therapy. Would you do anything different? Why or why not.
Walden University Asynchronous Paper

ITS 839 University of the Cumberlands Week 12 Objective and Research Questions

ITS 839 University of the Cumberlands Week 12 Objective and Research Questions.

Use the Chapter 3 document provided and develop an outline for your Chapter 3. Write the 1st paragraph for this document where you state your objectives and the research questions that will be addressed with the Research Design in Chapter 3.Note: you may not fully have developed Chapter 3 yet, but its important to understand what you have developed, so your instructor can assist you in areas needing guidance. Keep working on chapter 3, identifying issues, adding more research, etc., Even in weeks that do not specifically do not mention it, keep working on your chapter 3.Please makes sure to check your SafeAssign Report, anything over 1% will be checked by your instructor. keep working on your proposal and submit to Week 11 Final Proposal.Need 4 pages without header and references
ITS 839 University of the Cumberlands Week 12 Objective and Research Questions

Opioid Addiction and Abuse

essay helper free Opioids are a class of drugs that are used in the management of pain, and they represent a breakthrough in palliative medicine. Some major developments in the administration of these drugs have enabled them to be among the prescription drugs in health institutions. The drugs, however, have a characteristic of being euphoric and addictive, and patients have developed physical and psychological dependence during treatment. Most of the factors causing dependence of opioids are mainly centered on the individual using them for pain management, and include the use of other psychoactive drugs and pre-existing mental conditions. Bio-psychosocial stressors are also established predisposing factors for opioid abuse. The abuse has fatal effects on some of the patients with other patients developing lifelong complications. Investigations that may be used to monitor and detect opioids use and abuse include the use of urine sampling. Some of the interventional methods include behavior therapy. Introduction Opioids have widely been used in the, management of chronic pain in many health institutions, with the drugs being prescribed to other patients for management of some categories of acute pain. A major challenge that has emerged with the use of these drugs, however, is the addiction and dependence associated with them. The problem has caused financial and health problems for the patients who are unlucky to develop the dependence. On a global assessment of the problem, the economy is greatly affected with opioid dependence contributing significantly to the health budget. The people at risk of developing opioid dependence include the individuals with chronic pain and those with other underlying mental disorders or substance use disorders. This paper examines the abuse of prescription opioids, the effects to the patients and some of the complications that the dependence associated with it may have on them. Opioid abuse Opioids have been used extensively in the management of pain, and this is because they contain analgesic and euphoric properties (Knisely et al., 2008). Some of the factors that have also facilitated the increase in the use of opioids in the management of chronic pain as Portenoy states include the “introduction of high-dose, extended release oral tablet formulations of opioids with good bioavailability” (1996). This means that the drugs can easily be prescribed to patients, as opposed to the traditional methods which required monitored in-patient medication. The abuse of prescribed opioids has been on the rise in the recent past, with some researchers observing that the use surpassed street narcotics in the US (Webster,

Daemen College Stress Time Management and Extrinsic Motivations Discussion

Daemen College Stress Time Management and Extrinsic Motivations Discussion.


     1/Discussion Question: Module 5
Many of you have noticed an association between periods of stress, such as during exams, and getting sick. Discuss 2 strategies that you commonly use to deal with stress in your life, then think critically about them. Based on what you’ve learned in this chapter, how effective are the techniques you rely on? Do some of your strategies work better for some forms of stress whereas some are better suited to other situations? What could you be doing differently to manage stress in your life and become a better coper? Make sure to use your text as a reference?
2/Assignment: Module 5
Think of something that you’re motivated to accomplish: achieve in school, excel at a sport, improve your love life, change some unhealthy habits. Discuss specifically as you can what your current behavior is and what your desired end goal should be. Do you find that a combination of both intrinsic and extrinsic motives are diving your behavior as you seek to progress from Point A to Point B? For the goal you’ve selected, do environmental factors outweigh genetic ones in attaining your outcomes.  Make sure do also discuss what motivation is and the difference between intrinsic and extrinsic motivation.
Daemen College Stress Time Management and Extrinsic Motivations Discussion

Crafting a Compensation and Benefits Plan

Crafting a Compensation and Benefits Plan.

Now that you have considered how to recruit and retain the employees you want in your organization, create a compensation and benefits package using this business proposal format. The package must be consistent with the objectives of job satisfaction for the valuable employees in an organization of your design.Include the following:Salaries and benefits packages of comparable organizations in the same industry.What employees working in the 21st century consider to be benefits (see this week’s recommended readings for a start).What helps to keep employees engaged in their work (see State of the American workplace: Employee engagement for U.S. business leaders (Links to an external site.) and Surprising, Disturbing Facts from the Mother of All Employee Engagement Surveys (Links to an external site.) for some ideas).Please review the Word 2010 create and edit tables (Links to an external site.) video. Closed captioning and transcript of the video is provided in the tool bar of the video playerYour business proposal must be formatted according to APA style as outlined in the Ashford Writing Center, must include a separate reference page, and must include citations from the text and at least four scholarly sources, one of which must be from the Ashford University Library.
Crafting a Compensation and Benefits Plan