Creating Purchase Requests based on the product replenishment

Not out of the box. You would have to look at customization for that.

The default process for replenishments by purchases is:

1. On the Prepare Replenishments screen, select the items and quantity to process, by warehouse.
2. On the Create Purchase Orders screen, you create the POs based on the replenishment
3. Issue the Purchase Orders (print or email)
4. Process the Purchase receipts when received.

Please see the help article for more information: Replenishment Through Purchases: General Information

If you need specific approval processes for the replenishment items, you could set up specific rules that look at the PO lines for lines with the line type of  “Goods for RP”