* Brambles shares hit two-year high (Adds valuation, background): (Reuters) - Australian logistics group Brambles Ltd is selling its plastic containers business to private equity firm Triton and Abu Dhabi’s wealth fund in a $2.51 billion deal, earmarking proceeds for a buyback and sending its stock higher. Brambles said on Monday it planned to return up to $1.95 billion to shareholders from the $2.36 billion it expects in proceeds from the sale. Its shares jumped as much as 8.1 percent, before settling 2.8 percent higher at a two-year high, while the broader market rose 0.3 percent.