Unlike most other electrophilic aromatic substitutions, sulfonation is often reversible (see Section 17-4). When one sample of toluene is sulfonated at 0 °C and another sample is sulfonated at 100 °C, the following ratios of substitution products result:
Isomer of the Product 0 °C 100 °C
o-toluenesulfonic acid 43% 13%
m-toluenesulfonic acid 4% 8%
p-toluenesulfonic acid 53% 79%
(a) Explain the change in the product ratios when the temperature is increased.
(b) Predict what will happen when the product mixture from the reaction at 0 °C is heated to 100 °C.
(c) Because the SO3H group can be added to a benzene ring and removed later, it is sometimes called a blocking group. Show how 2,6-dibromotoluene can be made from toluene using sulfonation and desulfonation as intermediate steps in the synthesis.
Week 4 Mon 9/12 CH 4 Schedules of Reinforcement : specify which responses will be followed by the reinforce 1. Continuous Reinforcement Schedule: every instance of the behavior is followed by the reinforce a. Acquisition: the development of a new behavior through reinforcement i. Ex: when they first begin a behavior, you will reinforce every time they do the behavior until it is well-established. This is when you switch to intermittent reinforcement schedule 2. Intermittent/partial reinforcement schedule: not every instance of the behavior is followed by the delivery of the reinforce a. Maintenance: continuation of an operant behavior with intermittent reinforcement i. Ex: used to maintain; helps operant behavior stay in place for a long period of time b. Behaviors that are reinforced continuously are extinguished very easily and rapidly; if you’re only reinforced every once in a while, the behavior will keep on i. Skinner came up with this idea in rats- they will keep pressing the lever because they never know when the food is going to come ii. Ex: gambling pays out sometimes (they get lured in because sometimes they do win and they don’t understand probability and statistics); creates superstition because sometimes it is true based on probability