Propylene, a byproduct of oil refining and natural gas processing, is the most important raw material in the petrochemical industry after ethylene and is used for production of other organic chemicals.
Payvandi described propylene as perennially valuable as "gold”, saying Iran is best positioned to have the "pulse” of the global market for the substance as well as methanol in its hand.
Iran is already the biggest producer of methanol, with the volume set to grow even further as new projects are coming on stream.
"In any case, we will become a methanol giant; so this is a good chance to work on the technology for converting methanol to propylene,” he said.
Declines in the prices of methanol have sparked concerns and criticism from some quarters about economic sense of the project.
Payvand brushed aside those assessments, saying the Chinese will probably need to import methanol for years to come while the economy of propylene and its subsidiary components is to methanol.
"There are massive capacities being created in China. If it had no economic justification, the Chinese would have not invested in the sector at this level.”
Payvandi said with the transfer of the propylene technology, Iran will have also access to many downstream products such as acetone, phenol and propylene oxide.
 Iran is building the world’s largest methanol plant which the country is touting as a rival to US shale gas.
The Kaveh mega methanol project, being implemented in the Persian Gulf city of Bandar Dayyer, is 70% complete, Payvandi said in February.
Iran hopes to raise its methanol production capacity to 25 million tons per year in the next five years and establish itself as the biggest supplier of the product.

Agreement on New Oil Payments
Iran and China have also agreed on a new arrangement for crude oil payments under which Beijing will reimburse part of the money owed to Tehran in cash, a leading Iranian trader said on Monday.
China is the biggest buyer of Iran’s crude oil, purchasing more than 440,000 barrels each day, but Tehran imports goods instead of hard currency for its oil sales.
Asadollah Asgarowladi, chairman of Iran-China Chamber of Commerce, said the two countries have now agreed on making the payments partly in cash or transferring the money to a third country for imports.     
"We wanted to transfer part of the money for our exports to other countries such as South Korea and Japan for imports or receive it in cash. Hence, consultations were made and an agreement was reached in this regard.
"Under the new agreement with Chinese authorities, it was decided that after a commission rebate, the balance of the money from oil and gas exports is returned to Iran,” Asgarowladi said.
Iran can sell around 1 million barrels per day of oil under a preliminary nuclear agreement but the country has to use a maze of routes to receive its money.
Asgarowladi however said there is no problem for payments of the oil money by the Chinese, without specifying the currency with which the two countries are trading.
China is also Iran’s biggest trade partner. Asgarowladi said annual transactions border around $52 billion, with Iran’s exports accounting for 55% of the trade.   
Transactions, he said, will grow 20% every year under Iran’s vision plan irrespective of the results of nuclear talks which are currently at the final stretch.
"Trade relations between Iran and China are looked at from a long-term perspective and are not tied to the continuation or removal of sanctions.”
Asgarowladi, however, acknowledged that "minor differences” exist between the two countries over the quality of the Chinese goods.
Chinese goods have flooded the Iranian market in recent years, leaving many domestic production units in dire straits.
"We believe that the quality of Chinese goods exported to Iran must be improved and the ground be paved for an increase in investments by both countries in each other and by their joint companies,” Asgarowladi said.
He also said there are plans in the works for joint production in Iran which targets the regional market.