The most interesting and useful aspect of organic chemistry is the study of reactions. We
cannot remember thousands of specific organic reactions, but we can organize the reactions
into logical groups based on how the reactions take place and what intermediates are
involved. We begin our study by considering the halogenation of alkanes, a relatively
simple substitution of a halogen for a hydrogen that can occur in the gas phase, without
a solvent to complicate the reaction. In practice, alkanes are so unreactive that they are
rarely used as starting materials for laboratory organic syntheses. We start with alkanes
because we have already studied their structure and properties, and their reactions are
relatively uncomplicated. Once we have used alkanes to introduce the tools for studying
reactions, we will apply those tools to a variety of more useful synthetic reactions.
Writing the overall equation, with the reactants on the left and the products on the
right, is only the first step in our study of a reaction. If we truly want to understand a
reaction, we must also know the mechanism, the step-by-step pathway from reactants
to products. To know how well the reaction goes to products, we study its
thermodynamics, the energetics of the reaction at equilibrium. The amounts of reactants
and products present at equilibrium depend on their relative stabilities.
Even though the equilibrium may favor the formation of a product, the reaction
may not take place at a useful rate. To use a reaction in a realistic time period (and to
keep the reaction from becoming violent), we study its kinetics, the variation of reaction
rates with different conditions and concentrations of reagents. Understanding the
reaction’s kinetics helps us to propose reaction mechanisms that are consistent with the
behavior we observe.
The most interesting and useful aspect of organic chemistry is the study of reactions. Wecannot remember thousands of specific organic reactions, but we can organize the reactionsinto logical groups based on how the reactions take place and what intermediates areinvolved. We begin our study by considering the halogenation of alkanes, a relativelysimple substitution of a halogen for a hydrogen that can occur in the gas phase, withouta solvent to complicate the reaction. In practice, alkanes are so unreactive that they arerarely used as starting materials for laboratory organic syntheses. We start with alkanesbecause we have already studied their structure and properties, and their reactions arerelatively uncomplicated. Once we have used alkanes to introduce the tools for studyingreactions, we will apply those tools to a variety of more useful synthetic reactions.Writing the overall equation, with the reactants on the left and the products on theright, is only the first step in our study of a reaction. If we truly want to understand areaction, we must also know the mechanism, the step-by-step pathway from reactantsto products. To know how well the reaction goes to products, we study itsthermodynamics, the energetics of the reaction at equilibrium. The amounts of reactantsand products present at equilibrium depend on their relative stabilities.Even though the equilibrium may favor the formation of a product, the reactionอาจใช้สถานที่เป็นประโยชน์ การใช้ปฏิกิริยา ในเวลาจริง (และไปให้ปฏิกิริยาจากเป็นรุนแรง), เราศึกษาจลนพลศาสตร์ของ การเปลี่ยนแปลงของปฏิกิริยาราคาพิเศษพร้อมเงื่อนไขที่แตกต่างกันและความเข้มข้นของ reagents ทำความเข้าใจเกี่ยวกับการจลนพลศาสตร์ของปฏิกิริยาช่วยให้เราเสนอกลไกปฏิกิริยาที่สอดคล้องกับการลักษณะที่เราสังเกต
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