Examples of reactive change in the following topics:
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- Different carboxylic acid derivatives have very different reactivities, acyl chlorides and bromides being the most reactive and amides the least reactive, as noted in the following qualitatively ordered list.
- The change in reactivity is dramatic.
- In this two-stage mechanism bond formation occurs before bond cleavage, and the carbonyl carbon atom undergoes a hybridization change from sp2 to sp3 and back again.
- In principle all steps are reversible, but in practice many reactions of this kind are irreversible unless changes in the reactants and conditions are made.
- Finally, anhydrides and esters have intermediate reactivities, with anhydrides being more reactive than esters.
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- Chemical Reaction: A transformation resulting in a change of composition, constitution and/or configuration of a compound (referred to as the reactant or substrate).
- Reactant or Substrate: The organic compound undergoing change in a chemical reaction.
- Other compounds may also be involved, and common reactive partners (reagents) may be identified.
- Catalysts do not change equilibria positions.
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- The alkanes and cycloalkanes, with the exception of cyclopropane, are probably the least chemically reactive class of organic compounds.
- The practical importance of this reaction cannot be denied, but the massive and uncontrolled chemical changes that take place in combustion make it difficult to deduce mechanistic paths.
- No other common reaction involves such a profound and pervasive change, and the mechanism of combustion is so complex that chemists are just beginning to explore and understand some of its elementary features.
- In small-ring cyclic compounds ring strain can be a major contributor to thermodynamic stability and chemical reactivity.
- Changes in chemical reactivity as a consequence of angle strain are dramatic in the case of cyclopropane, and are also evident for cyclobutane.
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- The electropositive nature of the metal atom or group is an important factor influencing the reactivity of these reagents.
- The carbon-magnesium bond of Grignard reagents is about 20% ionic, and they have proven to be somewhat less reactive.
- Alkylmercury and lead compounds are the least reactive commonly studied organometallics.
- Dialkylmercury compounds are much less reactive, and can be mixed with water or alcohol without change.
- These serve as a reminder that oxidative conditions should be avoided when using reactive organometallic compounds.
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- Depending on the reduction potential of the metal, the reactivity of organometallic compounds varies markedly, the most reactive requiring low to moderate temperatures and inert conditions (atmosphere and solvents) for preparation and use.
- In general, the reactivity parallels the ionic character of the carbon-metal bond, which may be estimated from the proton and carbon chemical shifts of methyl derivatives.
- All these metals have strong or moderate negative reduction potentials, with lithium and magnesium being the most reactive.
- Halide reactivity increases in the order: Cl < Br < I.
- For example, simple alkyl lithiums are largely hexameric clusters in hydrocarbon solvents, but change to tetrameric and dimeric forms in various ether solvents.
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- This change manifests itself in a change in the phase of the elements from gas (F2, Cl2) to liquid (Br2), to solid (I2).
- This reactivity is due to high electronegativity and high effective nuclear charge.
- Fluorine is one of the most reactive elements.
- Fluorine's reactivity means that once it does react with something, it bonds so strongly that the resulting molecule is inert and non-reactive.
- Highly reactive fluorine is not included in the picture.
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- Thus, chloride anion is much more stable and less reactive than is hydroxide anion, so the former is a better and more common leaving group.
- Lastly, reactions #3 and #6 illustrate differences in the reactivity of carbonyl compounds.
- Thus, acid chlorides are very reactive with a wide range of nucleophiles, including water and alcohols (eq. 3).
- This is because the leaving group has changed from hydroxide anion to water (the acidity of the conjugate acid H3O(+) is nearly that of HCl).
- We can increase the electrophile reactivity by converting the ester to its conjugate acid, CH3C(OH)OC2H5(+).
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- Reactive attachment disorder is a childhood condition characterized by markedly disturbed ways of relating socially to others.
- Reactive attachment disorder (RAD) is described in clinical literature as a severe and relatively uncommon disorder that can affect children.
- Although increasing numbers of childhood mental health problems are being attributed to genetics, reactive attachment disorder is by definition based on a problematic history of care and social relationships.
- Such a failure could result from severe early experiences of neglect, abuse, abrupt separation from caregivers between the ages of six months and three years, frequent change of caregivers, or a lack of caregiver responsiveness to a child's communicative efforts.
- Summarize the diagnostic criteria, etiology, and treatment of reactive attachment disorder
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- The reactivity of the halogens decreases in the following order: F2 > Cl2 > Br2 > I2.
- All the hydrogens in a complex alkane do not exhibit equal reactivity.
- These results suggest strongly that 2º-hydrogens are inherently more reactive than 1º-hydrogens, by a factor of about 3:1.
- Further experiments showed that 3º-hydrogens are even more reactive toward halogen atoms.
- Since the hydrogen atom is common to all the cases cited here, we can attribute the differences in bond dissociation energies to differences in the stability of the alkyl radicals (R3C·) as the carbon substitution changes.