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Escalating geopolitical instability in the Middle East has thrown the global bromine supply chain into disarray. Within a few months, bromine quotations more than doubled as shipments from the region virtually ground to a halt, squeezing the availability of standard diquat dibromide. Amid this upheaval, Nanjing Red Sun Co., Ltd. stands among the few Chinese suppliers still delivering consistent volumes, underpinned by an exclusive, patented diquat dichloride technology purposefully developed ten years ago. The innovation substitutes chlorine for bromine, thereby decoupling production from the erratic bromine market.
Israel and Jordan together supply upwards of 35% of worldwide bromine output, while China sources 65% of its consumption from abroad—46% from Israel and 19% from Jordan. Once the Middle East conflict erupted, export logistics seized up, effectively severing China’s inbound flow. Consequently, bromine list prices rocketed from RMB 34,000 per metric ton at the turn of the year to RMB 72,000, a doubling that was largely notional since few deals materialized. By the time of this report, offers had surged to RMB 80,000 per ton.
With bromine accounting for more than half of diquat dibromide manufacturing costs, the feedstock bottleneck has directly throttled output. Key producers—Shandong Luba, Yonon, Red Sun, and Noon—have scaled back capacity utilization, and many smaller operators have been forced to idle plants entirely. The domestic market has tightened markedly, and delivery cycles have stretched to two or three times their typical length. Diquat dibromide technical concentrate (TK) is now priced around RMB 26,000–27,000 per ton, returning to levels last observed during June–July 2023.
As paraquat faces mounting regulatory bans and restrictions worldwide, diquat has become an indispensable non-selective burndown alternative, with steady global demand exceeding 50,000 metric tons per year and roughly 80% destined for export markets. The ongoing supply cut is sending shockwaves through major agricultural regions. Brazil’s annual requirement of nearly 10,000 tons is now confronted by a rapidly widening spot shortage, directly impairing desiccation and weed control in soybean and corn systems. Unmet replacement demand is also building across Southeast Asian nations, while U.S. and EU markets have begun to register price increases in response.
Red Sun achieved a critical manufacturing advance in 2016, engineering a rapid synthesis pathway that replaces bromide with chloride while preserving the diquat cation architecture. This innovation eliminated bromine reliance at the molecular design stage. Presently, a Red Sun subsidiary is the only Chinese entity with legal clearance to produce diquat dichloride mother liquor and soluble concentrate (SL), backed by a global patent and a 20,000-ton annual capacity on an active-content basis.
Measured against conventional dibromide, the dichloride variant offers three structural edges:
Supply chain resilience – The necessary chlorine, procured internationally, costs roughly RMB 300 per ton, a negligible fraction of bromine’s RMB 72,000 per ton. This cost insulation allows uninterrupted manufacturing irrespective of bromine price cycles.
Upgraded bioefficacy – At equivalent dose rates, field performance reaches 1.4 times that of the dibromide standard. Symptoms appear within two hours, residual activity persists for 20–25 days, and the molecule undergoes rapid passivation and inactivation upon soil or water contact, leaving behind no residues and qualifying as a green input.
Full-scenario versatility – The formulation is registered for non-crop land weed management, pre-harvest desiccation in potatoes, cotton, and soybeans, inflorescence suppression in sugarcane, and can be deployed in high-latitude autumn/winter cropping systems thanks to its low-temperature tolerance.
During June 2021, a field trial was carried out on farmland in Zhanhua, Shandong Province, examining diquat dichloride 20% SL against a mixed northern weed community comprising barnyard grass, green foxtail, crabgrass, horseweed, reed, and seepweed. The peak temperature on the application day was 32°C. Results are summarized below.
Table 1 – Weed control performance of diquat dichloride 20% SL in Zhanhua, Shandong (June 2021)
Treatment | Rate (ml per sprayer load) | Assessment at 4 days | Assessment at 7 days |
|---|---|---|---|
Diquat Dichloride SL | 150 ml | Broadleaf and the majority of grassy weeds desiccated; a limited number of reed and barnyard grass plants survived. | Barnyard grass showed a tendency to regreen; remaining weeds stayed fully desiccated. |
Diquat Dichloride SL | 200 ml | A sparse population of barnyard grass plants was not entirely killed; all other species were completely desiccated. | Barnyard grass exhibited some regrowth; other weeds remained controlled. |
Diquat Dichloride SL + Adjuvant | 150 + 4 ml | Only a few barnyard grass plants were not completely controlled; all other weeds desiccated. | Slight regreening occurred on a small number of barnyard grass plants; remaining weeds remained fully desiccated. |
Diquat Dichloride SL + Adjuvant | 200 + 4 ml | Complete desiccation of all weed species present. | Minimal regreening of a few barnyard grass plants was observed; the remainder stayed completely desiccated, representing optimal efficacy. |
The trial findings confirm that diquat dichloride delivers strong control of broadleaf weeds and most grass weeds. At the lower 150 ml rate, the majority of weeds were desiccated within four days. Elevating the dosage to 200 ml and incorporating an adjuvant further elevated control of challenging species like reeds, advanced green foxtail, and juvenile crabgrass, reaching optimum efficacy levels. Newly emerged barnyard grass proved somewhat more tolerant, though control could be markedly enhanced by a higher use rate or adjuvant inclusion.
Figure 1: Visual effect at 4 and 7 days post-application of diquat dichloride 20% SL at 150 ml per sprayer load
Figure 2: Visual effect at 4 and 7 days post-application of diquat dichloride 20% SL at 200 ml per sprayer load
Figure 3: Visual effect at 4 and 7 days post-application of diquat dichloride 20% SL + adjuvant at 150 ml + 4 ml per sprayer load
Figure 4: Visual effect at 4 and 7 days post-application of diquat dichloride 20% SL + adjuvant at 200 ml + 4 ml per sprayer load
Figure 5: Visual effect at 4 and 7 days post-application of diquat dichloride 20 AS treatment + adjuvant at 100 ml + 4 ml per sprayer load
The bromine crisis lays bare how geopolitical risk can cascade into global agricultural supply systems. Through early commercialization of a patented chlorine-based diquat, Red Sun has preserved reliable product flows while wide swaths of the market remain paralyzed. The product’s differentiating strengths—in supply security, manufacturing economics, and field performance—have been conclusively demonstrated in trials against the diverse weed flora of northern China. As the global diquat shortfall widens, this “China solution” provides a workable alternative for cornerstone production areas such as Brazil and Southeast Asia.
