Capacity of methyldiethoxyphosphine, key intermediate of glufosinate, being expanded quietly in China

According to Phillips McDougall and KLEFFMANN , global sales of glufosinate rose from $450 million in 2012 to $1.050 billion in 2020, becoming the fastest growing non-selective herbicide. These figures showed that the future glufosinate market will benefit from the following:

-  Continued worldwide prohibition or restriction of paraquat.

-  Growing resistance to glyphosate.

-  Continued promotion and penetration of glufosinate-tolerant GM crops， Especially China’s industrialization process for planting GM crops in an orderly manner.

Since China banned paraquat in 2016, Chinese manufacturers have begun to actively undertake glufosinate production. Currently, many production facilities are in the planning stage or under construction. A report published by GF Securities in 2020 showed that market players misunderstood the supply-side of glufosinate, but in recent years, the production capacity of glufosinate has been rising. It added that while 2018-2019 witnessed the start of new centralized productions of glufosinate, most of the new production capacity was for methyldiethoxyphosphine, which is the intermediate of glufosinate, whilst the new capacity of the intermediate, methyldiethoxyphosphine, is going slower than with glufosinate due to technical difficulties.

However, AgroPages learned that over the last two years, newbuilds of methyldiethoxyphosphine production facilities has been developed in parallel with newbuilds of glufosinate and L-glufosinate. Many new glufosinate and L-glufosinate facilities are being built, while newbuilds of methyldiethoxyphosphine facilities are being constructed quietly.

Glufosinate and L-glufosinate newbuild

In recent two years, more than 13 manufacturers have planned or have built glufosinate plants, totaling more than 162,000 tons on production. More than five manufacturers have planned or have built L-glufosinate plants, as shown in Table 1.

Table 1   Glufosinate & L-glufosinate projects under planning or construction

in China in last 2 years (incomplete statistics)

Newbuild of methyldiethoxyphosphine plants

Methyldiethoxyphosphine is an important organic chemical intermediate of pesticides, pharmaceuticals and synthetic materials, which is not only used for the synthesis of burndown herbicides, such as glufosinate, fenitrothion and organophosphorus pesticides like MAP insecticides, but it can also be used for the synthesis of flame retardant materials and building materials, as well as additives.

Over the last two years, 178,000 tons of methyldiethoxyphosphine capacity has either been planned or already built. Part of this capacity were launched by glufosinate or L-glufosinate manufacturers while some were launched by intermediate manufacturers. Previously, the production of methyldiethoxyphosphine was primarily centralized in Hubei Province, but it later spreads to the provinces of Shandong, Inner Mongolia and Ningxia, as shown in Table 2.

Table 2   Methyldiethoxyphosphine projects under planning or construction

in China in last 2 years (incomplete statistics)

Methyldiethoxyphosphine production process

The Aluminum-Strecker Method was adopted by some manufacturers to produce methyldiethoxyphosphine under the following process: Chloromethane, phosphorus trichloride and aluminate powder are used as raw materials to first obtain methylphosphonous dichloride, which is reacted for esterification with absolute ethyl alcohol, therefore, resulting in methyldiethoxyphosphine.

Manufacturers that adopted this method include Wynca, Honghu Yitai, Panshijiahengbao, Inner Mongolia Haopu, Gansu Binnong, Shandong Heyifeng and Liaoning Jiajialong.

Other methods: Methane, phosphorus trichloride and carbon tetrachloride are used as raw materials, being high temperature reacted to obtain phosphorus dichloride after distillation, which is then esterified with ethyl alcohol and liquid ammonia, to be rectified, thus resulting in methyldiethoxyphosphine.