China’s Carbazole Market Looks Promising

By Sang Jianxin, CNCIC

I. Capacity and output are increasing

Anthracene oil is a very important component of coal tar. Carbazole and refined anthracene are two important aromatic materials distilled from anthracene oil, of which carbazole has higher economic value. In recent years, the price of carbazole is far higher than that of refined anthracene. Therefore, producing carbazole has become the primary source of profits for coal tar processing enterprises. Worldwide, about 90% of the total carbazole output is obtained from coal tar.
   In 2011, major carbazole producers in China included Shanghai Baosteel Chemical Co., Ltd., Yancheng Department Hundred Industrial Co., Ltd. (formerly Yancheng Jianghai Chemical Group), Henan Baoshun Technology Co., Ltd., Yunnan Zhongyi Coal Chemical Co., Ltd., Xiaoyi Wentai Fine Chemical Co., Ltd., Shanxi Desheng Chemical Co., Ltd. and Jiangdu Fubang Chemical Co., Ltd.
   Jining Kemocal Chemical Co., Ltd., a three-party joint venture of Yankuang Group Co., Ltd., Jining Coal Chemical Co., Ltd. and French engineering group BEFS,was the largest and most technologically advanced anthracene oil processing enterprise in China. The company has a crude anthracene processing capacity of 34 kt/a. It adopted technologies and key equipment from BEFS and CIBA (Switzerland). The new production units of the company were under construction in 2011.
   The 40 kt/a anthracene oil processing unit in Yunnan Zhongyi Coal Chemical Co., Ltd. was successfully put into operation on December 17, 2010.
   Several major anthracene oil processing and the carbazole production enterprises in China, such as Anshan Iron and Steel Industrial Chemical Company, were shut down because of a series of problems including environmental pollution, poor product quality and the financial crisis of 2008. In 2011, there were fewer than twenty carbazole producers in China with a total capacity of 10.8 kt/a. And their combined output in 2011 was 5.05 kt. Major carbazole producers in China are listed in Table 1.
Table 1 China’s refined carbazole producers in 2011 (t/a)
Company    Capacity
Jiangdu Fubang Chemical Co., Ltd.    400
Shanghai Baosteel Chemical Co., Ltd.    1 500
Yancheng Department Hundred Industrial Co., Ltd.    1 200
Anshan Natian Chemical Co., Ltd.    300
Liaoning Orient Petrochemical Co., Ltd.    200
Benxi Donghao Chemical Co., Ltd.    200
Hebei Shenzhouhongyuan Chemical Co., Ltd.    400
Shanxi Desheng Chemical Co., Ltd.    600
Xiaoyi Wentai Fine Chemical Co., Ltd.    800
Jining Kemocal Chemical Co., Ltd.    1 500
Henan Baoshun Technology Co., Ltd.    1 800
Yunnan Zhongyi Coal Chemical Co., Ltd.    1 400
Others    500
Total    10 800
   
   
   Both the production and sales of carbazole in the global market have been booming in recent years. As shown in Table 2, in the next few years, one carbazole production unit will be relocated and expanded to 1 000 t/a; and four new carbazole producers will be set up with a combined capacity of 3 280 t/a.
   If the units listed in Table 2 can all be put into operation by 2015, the total capacity of carbazole in China is expected to reach 15 080 t/a at that time. Considering the operating rates of China’s carbazole production units in the last several years and the economic development of China in the next few years, the total output will reach 9 100 t/a by 2015.
   
Table 2 Carbazole projects under construction or to be constructed in China (t/a)
Company    Location    Expected     Capacity    Condition
Xiaoyi Xinli Fine Chemical Co., Ltd.    Xiaoyi City, Shanxi Province    1 000        Passed the environmental-impact assessment in April, 2011

Heilongjiang Longmay Mining Group (Qitaihe Mining Area)    Qitaihe City, Heilongjiang Province    1 800    Passed the environmental-impact assessment in October, 2010
Hubei Sanonda Co., Ltd.    Jingzhou City, Hubei Province    480 (registered)    Started to build in  2012
Wanrong Baisheng Fine Chemical Co., Ltd.    Wanrong County, Shanxi Province    400        Put into operation in February 2012
Shanxi Hongte Chemical Industry Co., Ltd.    Jiaocheng County, Shanxi Province    600    Under construction
Total        3 280
   

II. Application fields

Carbazole has a wide range of applications. It can be used in the production of dyes, pigments, pesticides, pharmaceuticals, photovoltaic materials, synthetic resins, photosensitive materials, specialty inks, etc.
   Pigments and Dyes   Permanent violet RL is a kind of high-grade organic pigment of carbazole dioxathion widely used in automotive finish coatings and high temperature plastics. It has advantages such as high-temperature resistance and UV-resistance. Blue dyes made from carbazole, such as sulfur indanthrene blue RNX and hydron blue, have excellent adhesion properties and resistance to chlorine bleach. Other blue dyes made from carbazole include carbazole IDM, carbazole LR, the carbazole LB and carbazole L3B. Black dyes made from carbazole include carbazole black D. Carbazole can also be used to produce dioxazine carbazole violet, a violet pigment used in coatings, printing inks, carbon paper, etc.
   Pesticides and pharmaceuticals   Carbazole itself can be used as a plant growth regulator and a stabilizer for pesticides. Both chlorinated and nitro derivatives of carbazole can be used to synthesize pesticides. 9-Methylcarbazole is mainly used for the synthesis of carbadox, a veterinary medicine and animal feed additive which can accelerate the growth of pigs and increase feed conversion rate. 4-Hydroxycarbazole can be used for the synthesis of carvedilol, a fast-acting and long-term hypotensive drug with no side-effects. Other advantages of carvedilol include easy oral absorption and complete metabolism. Currently, only a few enterprises in China can produce carvedilol. 1,2,3,4-Tetrahydro-4-oxocarbazol is an important pharmaceutical intermediate used for the synthesis of anti-emetics for chemotherapy and N-methylcarbazolone, another important pharmaceutical intermediate. Three enterprises in China – Shandong Qufu Hongli Chemical Co., Ltd., Ningbo FINC Science and Technology Development Co., Ltd. and Shandong Institute of Applied Chemistry – have successfully developed synthesis technology for 1,2,3,4-tetrahydro-4-oxocarbazol. N-vinyl carbazole can be synthesized from carbazole. First, carbazole is reacted with potassium hydroxide to form potassium carbazole. Then it is reacted with ethylene oxide or vinyl chloride. N-vinyl carbazole can also be obtained directly from the reaction between carbazole and acetylene. In recent years, other derivatives and homologues of carbazole, such as 1,2,3,9-tetrahydro-9-methyl-4-oxocarbazole, tetrahydrocarbazole, 1,2,3,6-tetranitro carbazole, (9-carbazolyl)acetic acid and 3,6-dibromo-carbazole, are being developed to synthesize new pesticides and pharmaceuticals.
   Photovoltaic materials   Poly-N-vinylcarbazole, a photovoltaic polymer with excellent light-conductive property, can be synthesized using carbazole. First, carbazole is reacted with acetic acid to produce methyl carbazole, and then dehydrated to form N-vinylcarbazole, then polymerized to form the polymer. Poly-N-vinylcarbazole can be used as a heat-resistant high-frequency electrical insulating material having good heat resistance and chemical stability, a high softening point, low dielectric loss and good light-conduction. With the popularization of digital cameras, more research has been carried out to develop electric-conductive and light-conductive materials for use in photography. Both the copolymer of methyl carbazole and benzaldehyde and the condensation polymer of bromo-carbazole and carbazole are electrically conductive. Currently, many researchers in China and abroad are endeavoring to develop high-tech photovoltaic materials, some of which are very promising.  
   Synthetic resins   Many specialty resins can be synthesized using carbazole. For example, a linear phenolic varnish coating can be synthesized using carbazole, phenol and formaldehyde. The polyamide resin synthesized from the thermal condensation polymerization of amino-carbazole and dicarboxylic acid has excellent elastic and thermal stability. Moreover, carbazole can also be added into resins to modify their properties in order to fulfill the requirements of various applications.
   Other materials   A high performance concrete water-reducing agent can be synthesized by the condensation polymerization of carbazole, phenol and formaldehyde. Carbazole can be used to synthesize stabilizers for lubricating oils and heat transfer oils. A specialty surfactant can be synthesized using carbazole and ethylene oxide. Carbazole and its derivatives can also be used in the production of explosives and rubber antioxidants.
   Of China’s total consumption of carbazole in 2011, 3 300 tons, that used in the dye (pigment) industry was about 1 580 tons, accounting for 48%; that used in the synthesis of pesticides and pharmaceuticals was about 885 tons, accounting for 27%; that used for the production of photovoltaic materials was about 190 tons, accounting for 6%; that use for the production of synthetic resins was 490 tons, accounting for 15%; that consumed in other fields was 155 tons, accounting for 4%. The domestic carbazole consumption structure in 2011 is shown in Figure 1.
   China is the world's largest producer and consumer of dyes, pesticides and pharmaceuticals. During the 12th Five-Year Plan period (2011-2015), in order to expand domestic demand and improve the standard of living, China will adjust and optimize the domestic industrial structure. With the rapid development of China’s economy, the structure of industries such as dyestuffs, pesticides and pharmaceuticals will be optimized and the application of carbazole will be expanded to new fields. It is expected that from 2011 to 2015, the consumption of carbazole will increase by 14.1% each year on average. By 2015, The consumption of carbazole in the production of dyes (pigments), pesticides and pharmaceuticals, photovoltaic materials, synthetic resins and other materials will reach 2700, 1550, 300, 850 and 200 tons, respectively. China’s carbazole consumption structure in 2015 Chinese is shown in Table 3.
   
Table 3 China’s carbazole consumption structure forecast for 2015 (tons, %)
    Dyes and pigments    Pesticides and pharmaceuticals    Photovoltaic materials    Synthetic resins    Others    Total
2015E    2700    1580    300    800    220    5600
YoY Growth (2011-2015)    14.3    15.6    12.1    13.0    9.2    14.1

III. Analysis and forecast of supply and demand for carbazole in China

China is a major exporter. In recent years, most of China’s increase in carbazole output is for export, and exports have more and more effect on the supply and demand for carbazole in China. In the future, with new capacity put into operation, the output, capacity and export volume of China are all expected to increase significantly. By 2015, the output, export volume and apparent consumption of carbazole in China will reach 9100 tons, 3500 tons and 5600 tons, with an average annual growth rate of 22.4%, 18.9% and 14.1%, respectively. The supply and demand for carbazole in China from 2011 to 2015 can be seen in Table 4.

Table 4 Supply and demand for carbazole in China from 2011 to 2015 (tons, %)
Year    Output     Import volume     Export volume     Apparent consumption  
2011    5050    0    1750    3300
2015E    9100    0    3500    5600
YoY growth (2011-2015E)    22.4    -    18.9    14.1

IV. Conclusion and suggestions
Carbazole has special chemical structure and is in short supply worldwide, while it has a wide range of applications. With the adjustment of the industrial structure and the improvement of environmental protection requirements worldwide, the coal tar processing industry has continued to shrink in the developed countries of Europe and North American. Therefore, the supply of carbazole in the global market will depend more on China. China’s carbazole industry should further optimize its structure, integrate resources, improve industrial concentration, make full utilization of carbazole resources, promote technological progress, improve product quality, develop high-purity products, foster world-class brands, develop downstream high-tech products and increase the proportion of these high value-add product in the carbazole export mix. Three traditional ways to produce carbazole are the sulfuric acid method, the selective solvent method and the vacuum distillation method. Currently in China, the sulfuric acid method has already been eliminated and most producers use the selective solvent method, which has shortcomings such as low product purity and high energy consumption. Vacuum distillation, the most advanced method, should be popularized since it can produce high-purity carbazole with less waste and emissions.