1 The Diels-Alder reaction is a conjugate addition reaction of a conjugated diene to an alkene (the dienophile) to produce a cyclohexene. 2  The simplest example is the reaction of 1,3-butadiene with ethene to form cyclohexene:3  The analogous reaction of 1,3-butadiene with ethyne to form 1,4-cyclohexadiene is also known: Due to the high degree of regio-and stereoselectivity (due to the concerted mechanism), the Diels-Alder reaction is a very powerful reaction and is widely used in synthetic organic chemistry.
Best Answer: Buyers have up 7 days to pay for an item before you as a seller can open an unpaid item case with ebay. They have a whole process they ask that sellers follow: Buyers automatically enter into a legally binding contract to purchase the item from the seller if they win an online auction or use the Buy It Now feature.
The time frame for getting a refund on eBay depends on the circumstances. It only takes a minute or two to log in and physically issue a refund. If youâre waiting for a refund for an item youâve returned then you must first wait for the return to be delivered. After that, the seller is supposed to issue the refund within 6 days. When a seller issues the refund there may be a delay in receiving the money depending on your original payment method. If you used a PayPal balance or bank account, the money will show up in PayPal right away.