Cyclopentane Q&A

Is cyclopentane an aromatic hydrocarbon?
Answer: alkanes, alkenes and alkynes belong to aliphatic hydrocarbons, while benzene, cyclohexane and cyclopentane belong to cyclohydrocarbons, and benzene is the aromatic hydrocarbon in cyclohydrocarbons. Cyclopentane, cyclobutane and ethyl cyclohexane are all cycloalkanes in cyclohydrocarbons.

Since the entry into force of Montreal Protocol in 1989, people began to look for an alternative to CFC-11 foaming agent. So far, the foaming agent for household appliances has gone through three stages of substitution, and the fourth generation foaming agent cyclopentane has also entered the alternative ranks.

N-pentane and isopentane are obtained from oil field light hydrocarbons by high-efficiency distillation. N-pentane can be used as desorbing agent for molecular sieve dewaxing process. After blending with isopentane in different proportions, it can meet the requirements of different foaming degrees. It can be used as high-efficiency foaming agent for expandable polystyrene. It can be mixed with cyclopentane and used as polyurethane foaming agent. Isopentane can be used as foaming agent for expandable polystyrene, foaming agent for polyurethane foam system, deasphalting solvent, solvent for catalyst production in polyethylene production, etc. It is generally mixed with cyclopentane and used as foaming agent for rigid polyurethane foam.
Important reminder:
1. Cyclopentane is flammable and explosive, with an explosion limit of (1.4-8.0)%. It is listed as class A and class B fire objects. Cyclopentane is also a volatile organic compound, with a volatile amount of 8.5kg/m2 per hour, with a faint pungent smell. Therefore, there are strict requirements for production equipment, plant, transportation and storage, as well as high requirements for the quality and safety of enterprise employees.
2. Cyclopentane itself has low toxicity and deasterification function. Once it touches the skin or splashes into the eyes, it should be washed with clean water immediately. Once cyclopentane leaks, it shall be diluted and dispersed with inert gas nitrogen immediately.

Cyclopentane Q & A

Is cyclopentane toxic?
Cyclopentane has low toxicity and degreasing function. Once it comes into contact with skin or splashes into eyes, it should be washed with clean water immediately.
Once cyclopentane leaks, it shall be diluted and dispersed with inert gas nitrogen immediately. In case of fire, within 50m
If it is listed as a disaster area, other personnel must stay away from the disaster area except fire fighting and command personnel.
4. Site management requirements
1) It is forbidden to visit during cyclopentane production. 2) The operators entering the foaming team must be the personnel on record of the safety committee. The entrants must wear the specified electrostatic clothes and no spiked shoes. 3) The staff and maintenance personnel entering and leaving the foaming shift must be registered. 4）
The staff entering the foaming team are strictly prohibited to carry mobile phones, and the personnel temporarily entering the foaming team must be kept under the supervision of the safety management office
When the mobile phone is turned off, it is strictly prohibited to dial the mobile phone; No smoking; It is strictly prohibited to carry lighters, matches, keys, etc; It is forbidden to be in danger
Arrange clothes in dangerous areas and do not comb your hair. 5) Except for the equipment installation and maintenance approved by the safety committee, open flame operations such as electric welding and gas cutting are strictly prohibited in the foaming team; It is forbidden to use metal objects that can produce sparks for knocking or grinding. 6) In case of level I alarm, anyone has the obligation to immediately report to the person in charge of production, contact the maintenance personnel to quickly find out the cause, and carry out key production monitoring at the same time; In case of level II alarm, all personnel must evacuate quickly to the designated safety area according to the emergency procedure. 7) During the holiday, the personnel on duty in the cyclopentane safety monitoring room shall contact the personnel in the general monitoring room.

Comparing the toxicity and volatility of n-pentane, isopentane, hexane, cyclohexane, n-heptane and n-octane, which is more suitable as butyl rubber solvent?
Answer: the butyl rubber solution production process solvent is mainly a mixed solvent of isopentane and chloroethane, with low toxicity. The temperature: – 80-70 ° C can polymerize at higher temperature and reduce energy consumption. Long operation cycle: 400-500hr, isobutene monomer conversion: 20% – 30%, polymer content in rubber solution is generally 10%. The solvent system has a great influence on the molecular weight distribution. Mixed solvents can improve the molecular weight distribution and reduce branching.

Can you analyze the advantages and disadvantages of cyclopentane and cycloisopentane as foaming agent?
Answer: the physicochemical properties of cyclopentane and ring / isopentane are the first. The boiling point is different. Isopentane is 28 degrees centigrade, cyclopentane is 49 C, compared with CFC-11 (boiling point 23.8 degree), isopentane is the closest. As a foaming agent, it is obvious that isopentane is more suitable than cyclopentane, and foaming agent is used in the foaming process of rigid polyurethane foam. The heat released by the reaction of polyether polyol and isocyanate is used to heat the foaming agent, and the foaming agent vaporizes when heated to produce foaming effect. Some overflow and some remain in the cell. Compare isopentane with cyclopentane. When isopentane is used, the reaction between polyether polyol and isocyanate is exothermic. When the temperature reaches more than 28 ℃, isopentane vaporizes and plays a foaming role, while cyclopentane has to wait until the reaction is exothermic? When the temperature reaches about 50 ℃, cyclopentane can vaporize and play the role of foaming. The physicochemical properties of cyclopentane and cyclo / isopentane are compared. Therefore, all refrigerator production lines imported in China using cyclopentane as hair agent must preheat the molds to a certain temperature, which is also the reason for the high ambient temperature of the foaming workshop. In order to preheat the mold, the foaming workshop needs a heat source to maintain a certain temperature, and this energy also needs a certain manufacturing cost. Using cyclopentane as the foaming agent has lower requirements on the environmental temperature and mold temperature of the foaming workshop than using cyclopentane as the foaming agent. The foaming process has lower requirements on the preheating and environmental temperature of the mold, which can save some energy, The cost can be appropriately reduced. Secondly, the physical and chemical properties of cyclopentane and cyclo / isopentane are different. CFC-11 is 0.008 (20 ℃) / W. (m.k) – 1, cyclopentane is 0.010 (20 ℃) / W. (m.k) – 1, and isopentane is 0.013 (20 ℃) / W. (m.k) – 1. Obviously, from the perspective of steam thermal conductivity, cyclopentane is closer to the steam thermal conductivity of CFC-11. The steam conductivity of the foaming agent is smaller, the better, because the foam is partially retained in the bubble, while the thermal conductivity of the foaming agent in the bubble will directly affect the heat transfer effect of the rigid polyurethane foam. The smaller the steam conductivity in the bubble, the better the insulation effect of the foam product. The vapor conductivity of isopentane is 0.003 (20 ℃) W. (m, K) – 1 higher than that of cyclopentane. Therefore, the formation of foam K is worse than cyclopentane foam. However, the thermal conductivity of foam is similar to that of cyclopentane system at low temperature. Analysis of the advantages and disadvantages of cyclopentane, ring / isopentane as blowing agent third. The vapor pressure of foaming agent is different. The boiling point of isopentane is lower. When compared with cyclopentane, isopentane is also gaseous when it is lower in temperature, so it has a certain supporting effect on foam, so that it has great help to the dimensional stability of foams. Therefore, the dimensional stability of the foam can be improved, so that the foam density can be reduced correspondingly, so that the customer satisfaction can be satisfied. Therefore, it is recommended to adopt cyclopentane / isopentane foaming when reducing the production cost of refrigerator. Compared with cyclopentane foaming technology, cyclopentane and cyclopentane / isopentane (7:3) foaming technology: it is mainly used in occasions with high requirements for thermal insulation performance but no fluorine substitution, which meets the requirements of national and international environmental protection and energy conservation.? At room temperature, pentane is still gaseous in pentane foaming foam. When foam material is low temperature, pentane is easily condensed into liquid pentane at the low temperature. Once this condensation occurs, the actual pressure of the mixed gas will gradually decrease with the decrease of temperature, resulting in pressure difference from atmospheric pressure. Meanwhile, cyclopentane condensation will play a role in the swelling of the foam. In this way, the stress of foam material is deformed. For CFC-11 foaming, the density of 32kg/m3 has enough strength to withstand the stress generated by pressure drop in the bubble. If pentane is foamed, the density must be increased to 35kg/m3, so that there is enough strength to withstand the stress and ensure that it has enough dimensional stability. When the dosage of formula water is 2 phr, the dosage of pentane is generally about 12 phr. Compared with F11, the dosage in the formula is less. In order to ensure dimensional stability, the density needs to be increased, and the core density of the box is 35kg / m3. The common foam thermal conductivity of the refrigerator is 0.0200 to 0.0210W/m.k, and the foam K value of the optimized system can reach 0.0195W/m.k cyclopentane, ring / isopentane (7:3) foaming technology, contrast ring / isopentane (7:3) foaming: in order to reduce the production cost of the refrigerator, the formation density of foam can be reduced by using ring / isopentane, and the dimensional stability of the foam is higher. The filling volume of refrigerator is 5% ~ 8% lower than that of cyclopentane foam, and the box core density is 33kg / m3. The thermal conductivity of the refrigerator foam is between 0.0210 and 0.0220W/m.k, but the energy consumption of the refrigerator is slightly higher than that of the cyclopentane system. In the same production line, cyclopentane or cyclopentane / isopentane can be used for foaming switching according to the requirements of the production order. Before switching, the combined polyether to be used for equipment and pipeline shall be cleaned and replaced before foaming with new foaming agent.

Why does the supply of cyclopentane products exceed the demand?
The reporter of electric appliance learned that at present, cyclopentane is still the foaming agent widely used in refrigerator, freezer and water heater enterprises. According to China’s HCFCs elimination plan, cyclopentane is also one of the main substitutes for HCFC-141b foaming agent because of its low toxicity, easy preparation, low price and zero ODP and GWP in the fields of refrigerators / freezers, solar water heaters, electric water heaters and small household appliances. At present, the main suppliers of cyclopentane in the Chinese market are Junyuan Petroleum Group, Beijing Dongfang Yakeli Chemical Technology Co., Ltd., Foshan Shunde Meilong cyclopentane Chemical Co., Ltd. and several foreign-funded enterprises.
A person in charge of Beijing Dongfang Yakeli Chemical Co., Ltd. told the reporter of electric appliance: “In 2014, the overall supply of cyclopentane in the market exceeded the demand, and the sales volume showed a downward trend. The downturn in the home appliance market was the most direct and main reason for the decline in cyclopentane sales. The sluggish production and sales of complete home appliance factories had a great impact on the upstream raw material enterprises supporting them. In addition, the promotion and application of HFC-245fa in recent years also seriously affected the sales of cyclopentane, Dongfang Asia Keli has begun to explore new foaming technology. ”
Although cyclopentane foaming technology has been very mature, the thermal conductivity of foam has always been about 20mW/ (M. K), and it is very difficult to continue to reduce. For the appliance industry that needs to raise energy efficiency level, it is “more than enough, but insufficient strength”. Due to its high cost performance, cyclopentane is still the mainstream foaming agent used in the household appliance industry, especially in the refrigerator industry. However, under the pressure of energy efficiency, many household appliance enterprises choose to mix cyclopentane with other new foaming agents.
HFC-245fa and hfc-365mfc
The identity of “transition” is embarrassing
It is understood that at present, the foaming technology of refrigerators abroad mainly adopts two foaming routes: one is represented by Europe, using cyclopentane or hfc-365mfc foaming technology; the other is represented by the United States, using pure hfc-245a foaming technology.
With the promotion of China’s HCFCs phase out plan, hfc-245a and hfc-365mfc have entered China as alternatives to cyclopentane and HCFC-141b for many years. In 2007, sijimuge cooperated with Honeywell to introduce HFC-245fa foaming agent and launched the world’s first green fluorine-free foaming solar water heater production line, leading the solar water heater industry into a fluorine-free Era. In 2009, Hisense Kelon refrigerator Large scale use of HFC-245fa foaming agent. So far, the promotion of HFC-245fa foaming agent in China’s household appliance industry has entered a fast lane.
It is worth mentioning that the HFC-245fa patent will expire in 2015, when some domestic enterprises can also put into operation. “HFC-245fa will no longer be monopolized, and the price may be more close to the people.” a technical director of Dow Chemical’s Greater China Polyurethane Products Division said excitedly. “This is very beneficial to the whole HFC-245fa market. In other words, if the price of HFC-245fa decreases, more manufacturers will use it, which will accelerate the promotion of HFC-245fa.”
However, because the price and GWP value do not meet the environmental protection requirements, HFC-245fa is not used as a pure foaming agent in the household appliance industry as in foreign countries, but is more mixed with foaming agents such as cyclopentane. In fact, the promotion of HFC-245fa in China’s household appliance industry is not so smooth. “After a short scenery, it may be lonely and exit.”
An industry expert who asked not to be named pointed out that from the perspective of enterprises, HFC-245fa foaming technology is relatively mature and is a good option under the background of promoting high energy efficiency in the industry. However, the GWP value of HFC-245fa is very high and the promotion is not encouraged at the national level.
A person in charge of Beijing Dongfang Yakeli believes that HFC-245fa is only a transitional product. Although enterprises continue to try HFC-245fa, the real promotion still needs a process. Many complete machine factories have not used HFC-245fa before, and the technology needs to be run in and improved. The person in charge clearly said, “we have no plan to put HFC-245fa into production.”
At the same time, HFC-245fa has also been banned in some foreign regions. In January 2015, the use of HFC-245fa will be banned in Europe; in 2016, the use of HFC-245fa will be banned in the United States. Zhou Zhengping, general manager of KANGLONG company, told the reporter of electric appliance: “Although China has no clear regulations on HFC-245fa at present, it will gradually prohibit the use of HFC-245fa in the future. Maybe China will have relevant regulations in the next two or three years. With the international control of greenhouse effect and carbon emission, it is expected that this kind of foaming agent will eventually be limited and eliminated.”
Guan Jifeng, a senior engineer of boxihua household appliances Co., Ltd., who has long realized that HFC-245fa will be limited in the future, stressed that boxihua resolutely does not consider using HFC-245fa.
Suwei group is a major supplier of HFC-365mfc. Similar to HFC-245fa, HFC-365mfc has advantages in thermal conductivity and boiling point, but it is limited because of high GWP value, large foam density and flammability.
The fourth generation foaming agent is expected to become the mainstream
In August 2012, whirlpool announced that all whirlpool refrigerators made in the United States, including whirlpool brand, Maytag, Amana, Jenn air and KitchenAid brand, use a new generation of liquid foaming agent hcfo-1233zd Trifluoropropene (LBA) In November 2013, Midea refrigerator announced that LBA was used in some energy-saving refrigerators and freezers produced by Midea in 2014. In September 2014, Honeywell announced that Haier adopted LBA in large capacity refrigerators produced. The behavior of the three home appliance giants jointly confirmed the fact that the fourth generation foaming agent is being favored by the industry.
Wang Lei, vice president of China Household Appliances Association, told the reporter of electrical appliances that LBA is non combustible, GWP value is extremely low, energy efficiency is 10% ~ 12% higher than cyclopentane, thermal conductivity is 8% lower than HFC-245fa, and polyurethane rigid foam foamed with LBA has good strength, dimensional stability and adhesion. “LBA foaming agent is similar to cyclopentane system in terms of foaming equipment and foaming process. It can directly replace cyclopentane without additional investment.”
In addition to Honeywell’s LBA, DuPont’s hfo-1336mmz (hexafluorobutene) Fea-1100 is also very representative. According to relevant DuPont sources, the GWP value of hfo-1336mmz is 2 and the ODP value is 0. On September 15, 2014, the fluorine chemicals business department of DuPont announced that it would fully start the large-scale commercial production of hfo-1336mzz through its factory in China in the second half of 2016. DuPont’s production line in China will become the world’s first large-scale production line of hfo-1336mzz In terms of commercial promotion, DuPont is conducting evaluation work with major users in polyurethane rigid foam industry, such as household appliance manufacturers such as refrigerators and water heaters, and users in refrigerated containers, so as to realize commercial application.
A person in charge of Dongfang Yakeli said, “we are also discussing the fourth generation foaming agent.” Zhou Zhengping pointed out that although some performance indexes of the fourth generation foaming agent are very good, the price is relatively high. It is still a problem whether it can be used as the mainstream foaming agent in the household appliance industry in the future. Maybe it will exist in the form of blending with cyclopentane.