Request for the process flow of oxidizing benzene to phenol (paid)

file:///C:/DOCUME%7E1/WENFEN%7E1.SCI/LOCALS%7E1/Temp/msohtml1/01/clip_image002.jpg file:///C:/DOCUME%7E1/WENFEN%7E1.SCI/LOCALS%7E1/Temp/msohtml1/01/clip_image004.jpg Isopropyl benzene; English name: isopropyl benzene, cumene. file:///C:/DOCUME%7E1/WENFEN%7E1.SCI/LOCALS%7E1/Temp/msohtml1/01/clip_image006.jpg Isopropyl benzene, cumene; also known as cumene. A colorless, aromatic liquid with a boiling point of 152.39°C. Industrially, all isopropylbenzene is produced by the alkylation of propylene and benzene (see color illustration); it is one of the main products that consume propylene. In 1982, the world’s production capacity for isopropylbenzene was around 5 Mt. A small portion of the isopropylbenzene produced was used as an additive in gasoline and for the manufacture of synthetic fragrances, while the vast majority (over 98%) was used to produce phenol and propylene. After 1942, American Shell Oil was the first to achieve industrial production of isopropylbenzene through the alkylation of propylene with benzene. Later, various countries developed many production methods for alkylation processes, which can be classified into liquid-phase and gas-phase methods based on the phase state of the reaction process. The gas phase method is used in most industrial applications. 　Liquid-phase method: Similar to the liquid-phase method used for the alkylation of benzene and ethylene to produce ethylbenzene, aluminum trichloride is typically used as a catalyst, with hydrogen chloride serving as a promoter. The reaction generally takes place at atmospheric pressure and

We have a benzene-isopropylbenzene-phenol process; I’m not sure if it meets your requirements. songligang@gmail.com, 15940841668

Has this technology been industrialized? As far as I know, it seems no industrial facilities are in operation. Recent Advances in the Direct Hydroxylation of Benzene to Phenol Abstract: This paper presents the recent advances in the direct hydroxylation of benzene to phenol using N2O, O2, and H2O2 as oxidants, and discusses the future prospects for this field. Keywords: benzene, phenol, hydroxylation, oxidation; Chinese classification number: TQ243.1+2. Phenol, also known as carbolic acid, is an important organic chemical raw material. It is primarily used in the production of phenolic resins, caprolactam, bisphenol A, adipic acid, aniline, alkylphenols, and salicylic acid. Additionally, it can be used as a solvent, reagent, and disinfectant. It has a wide range of applications in synthetic fibers, synthetic rubber, plastics, pharmaceuticals, pesticides, fragrances, dyes, and as an additive. Before World War I, phenol was primarily extracted from coal tar. As the demand for phenol continued to rise, people began to use chemical synthesis methods to produce it. The earliest chemical synthesis method for phenol was the sulfonation method, which was first developed in 1923 by the American company Monsanto. Subsequently, other production methods were introduced, such as the chlorobenzene method, the toluene oxidation method, the cyclohexane-cyclohexanol method, the isopropylbenzene method, and the direct oxidation of benzene. Currently, the main industrial method for producing phenol in the world is the cumene process. The phenol production process using isopropylbenzene has advantages such as high product purity and low consumption of raw materials and energy. However, the future development of this process may be constrained by its by-product, propyne. In the cumene process, the relative ratio of phenol to propylene is 3:5 (on a mass basis), and the balance between the supply and demand of phenol and propylene is a common issue. A major use of propylene is as a raw material for synthesizing the acrylic monomer methacrylate. In recent years, the production of methacrylates has gradually shifted to the isobutylene and isobutane route, resulting in a decreasing demand for propylene. Additionally, propylene is volatile and has a destructive effect on the ozone layer; therefore, overall, a purification process is required for propylene, and a large amount of energy is needed to recover and utilize unreacted benzene and isopropylbenzene. Therefore, in recent years, research has begun on production methods for synthesizing phenol directly from benzene as a starting material. The research results show that this method features simple process, high yield, and low environmental pollution, offering broad prospects for industrial development and application. The types of oxidants currently under study mainly include oxygen, hydrogen peroxide, and nitrous oxide, while the types of efficient catalysts developed include H-ZSM-5, supported ZSM-5 (Fe-ZSM-5, Na-ZSM-5), titanium silicalite TS-1, and hydroxyapatite. 1 Oxidation process using N2O as an oxidant: The American company Solutia and the Russian Boreskov Institute of Catalysts (BIC) [1] jointly developed a new process for the direct oxidation of benzene to phenol without the production of propylene as a by-product – the AlphOx process. This process uses a metal-modified zeolite molecular sieve as a catalyst to oxidize benzene with N2O to produce phenol. The reaction takes place in a fixed-bed adiabatic reactor operating in the gas phase at low pressure; after simple separation and distillation, phenol of high yield and high purity can be obtained. Repeated experimental results using BIC on catalysts show that acidic ZSM-5 and ZSM-11 zeolite catalysts containing iron, after being treated with steam at 500–900°C for 2 hours, can significantly increase the yield of phenol, suppress the combustion reaction between benzene and N2O, and delay catalyst deactivation; the half-life of such catalysts can reach 3–4 days. Furthermore, the benzene oxidation catalyst can be regenerated by purging the deactivated catalyst bed with air at high temperatures; the regenerated catalyst can fully regain its activity. The optimal composition for maintaining catalytic function even after 100 regenerations is one containing 0.45% (w) of Fe2O3, with a SiO2 to Al2O3 ratio of 100:1. Data on the technical and economic evaluation of the AlphOx process from the Stanford Research Institute in the United States show that the total capital investment required for this process is lower than that of a phenol production facility using the isopropylbenzene process of similar scale. Its net production costs are competitive, and it is not affected by fluctuations in the propylene market. “The AlphOx” phenol process features high selectivity, a simple process flow, and waste generation that is less than 2% of the amount of raw benzene used. It also enables effective integration of the phenol production facility with the adipic acid production facility, allowing for the effective utilization of the waste N2O produced during adipic acid synthesis, as well as the use of phenol either in adipic acid production or for sale as a commodity; hence, it is highly attractive to manufacturers of adipic acid. However, current pilot-scale study results show that the catalyst has poor selectivity and continuous operation cycle; the selectivity for phenol, expressed in terms of N2O, is low, so there is still a distance to go before industrial production can be achieved. Recently, Solutia and GTC Technologies [2] developed a one-step phenol production process that is said to maximize the utilization of propionic acid byproducts. This process is a gas-phase reaction of benzene with dinitrogen monoxide (N2O) under the action of a zeolite catalyst, featuring high selectivity; it yields a high yield of phenol, does not consume propylene, and produces no propylene by-products. Selective enhancement improves phenol distillation, enabling the production of resin-grade phenol. The solid-catalyzed gas-phase reaction of benzene is carried out in 3 steps, namely N2O preparation, the AlphOx process, and phenol purification: (1) N2O preparation. It is possible to use waste gas from one’s own dicarboxylic acid production process, or N2O produced by the catalytic oxidation of ammonia and air, or to combine these two methods. The diacid waste gas contains approximately 25%–30% N2O, nitrogen, oxygen, carbon dioxide, carbon monoxide, as well as NOx. After removing NOx, CO, and oxygen, the pre-treated gas can be sent to the reactor. The yield of N2O obtained by catalytic oxidation of ammonia with air is approximately 80%–95%. (2) AlphOx process. The reactants for this reactor are N2O, benzene, and inert components (N2, CO2, and H2O). The AlphOx reaction is exothermic, so the reactor operates in an adiabatic manner. Its reaction process involves connecting multiple reactors in series, with the operation cycle following a sequential reaction/regeneration scheme or a moving bed design, and the catalyst is transferred between the reactors and the regenerator. A gas circulation tower separates the reactor off-gases from unreacted benzene and crude phenol; the nitrogen obtained at the top of the tower is recycled to the reactor, while the material at the bottom of the tower is sent to a benzene stripping tower to recover benzene from the crude phenol, which is then sent on to purification processes. (3) Phenol purification. This process exhibits high selectivity for producing phenol from benzene. In the heavy-component column, crude phenol from the benzene stripping column is stripped of its heavy components in this column; the light phenol stream is sent to a purification column for the separation of light components, and the final product is sent to a phenol refining column to obtain resin-grade phenol. Compared with traditional production methods, the advantage of this process lies in its reduced investment costs, as well as lower costs for raw materials and utility services; it improves phenol selectivity, reduces waste generation, and does not produce propylene as a by-product. Compared to traditional methods, this process is more competitive for plants with small production scales. The Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences [3] conducted research on the gas-phase catalytic oxidation of benzene to phenol using FePO4, FePO4/SiO2, and Fe0.5Al0.5PO4 as catalysts, respectively. At a reaction temperature of 450°C, the conversion of benzene over the FePO4 catalyst was 2%, and the selectivity for phenol was 85% ； Using the FePO4/SiO2 catalyst, the conversion of benzene was 7% and the selectivity for phenol was 89% ； Fe0.5Al0.5PO4 as a catalyst can reduce the reaction temperature by about 100°C; at 350°C, the conversion rate of benzene is 3.5% and the selectivity for phenol is 60%. 2 Oxidation process using O2 as an oxidant. General Electric Company [4] proposed an economical and more widely applicable process in which benzene is selectively converted into phenol using air as an oxidant, with a vanadium-based catalyst. The catalyst is preferably an oxide or alkali metal salt of vanadium, niobium, or tantalum, containing both neutral electron-donating ligands and anionic ligands. 0.01 g of VO(acac), 0.02 g of picolinic acid, and 50 mL of benzene were added to a stainless steel tank (where acac refers to acetylacetone); the container was sealed with a lid equipped with a stirrer shaft and a condenser. It was heated to 100°C while stirring, and then pressurized to 6.9 MPa using air containing 2.1% hydrogen. After 18 hours, it was cooled, resulting in the formation of 0.012 g of phenol, with no other by-products. This indicates that 3.5 mol of phenol can be converted per mol of catalyst. However, to achieve industrial production, it is also necessary to increase the reaction rate and maintain high phenol selectivity. Suncoc Company [5] developed a production process for the direct oxidation of benzene to phenol, using molecular oxygen as an oxidant and chelates as catalysts. The key to this research is identifying the ligands required for the selective partial oxidation process (such as vanadium, niobium, copper, palladium, nickel, silver, etc.) in order to form suitable transition metal catalysts. In a continuously stirred reactor equipped with a gold plate, at 180°C and 5.58–5.78 MPa, using oxygen-containing nitrogen as an oxidant, vanadium-based chelates loaded on titanium dioxide (containing 1.2% metal) were used as catalysts, achieving a phenol selectivity of over 97% when the benzene conversion rate was 1%. This process uses inexpensive oxygen as an oxidant instead of nitrous acid, and its advantage is that it allows for the production of by-products without relying on propylene, a raw material whose supply is becoming increasingly scarce. The Korea Institute of Chemical Technology [6] has developed a one-step process for the direct oxidation of benzene to phenol. At a reaction temperature of 50°C, with a volume ratio of hydrogen to oxygen to nitrogen of 1:1:2, a solution composed of benzene and acetic acid in a 1:1 ratio (a slurry containing two different zeolite catalysts) was fed into the system; under the action of these catalysts, the selectivity for phenol produced was greater than 0.97%. The catalytic system consists of Y-zirconia and ZSM-5 zeolites, where the Y-zirconia contains 4% Pd and 1.1% adsorbed ethyl anthraquinone, and the ZSM-5 zeolite contains 2% titanium. The drawback of this system is its low yield. Niwa et al. [7] developed a method for the one-step conversion of benzene to phenol on a palladium membrane. Using a tubular reactor, a gaseous mixture of benzene and oxygen is fed into porous alumina tubes coated with a thin palladium film, while hydrogen is fed into the shell layer. Hydrogen is released on the outer surface of the palladium membrane and penetrates to the other side of the membrane where it reacts with oxygen, releasing reactive oxygen species. These reactive oxygen species attack benzene to produce phenol. At 250°C, the selectivity for phenol is 80%–97%, and the conversion rate of benzene is 2%–6% ； The yield of phenol at 150°C is 1.5 kg·(g·h)-1. Tokyo Koso Company in Japan [8] has developed a new technology for synthesizing phenol from benzene using a novel palladium catalyst. The new process uses zirconia as a carrier, coated with a mixture of palladium and tellurium powder as a catalyst. The process involves: adding benzene, oxygen, and hydrogen to a reactor filled with catalyst, then heating it; acetylation occurs first to produce phenyl acetate, after which water is added and ion exchange resin is used to decompose the mixture into phenol and acetic acid. Acetic acid is returned to the first reaction step for reuse. Although in the oxidative acetylation step at the first stage, the conversion rate of benzene is currently only 10% with 90% of benzene reacting to form phenyl acetate, almost 100% of phenyl acetate is converted into phenol. At present, the lifespan of the new catalyst has reached 8,000 consecutive hours (about 1 year). In addition to having a lower environmental impact, the new synthesis technology does not produce by-products such as propane or CO2. The entire process requires only 2 reaction steps, which significantly reduces equipment and energy costs. If the company increases the benzene conversion rate to 20%, the costs, including those related to equipment and operating expenses, will be lower than those of the original method. Currently, the company is further conducting research and development on issues such as catalyst activity and extending catalyst lifespan. The Japan Advanced Institute of Science and Technology (AIST), the National Institute of Industrial Technology, Maruzen Petrochemical Company, and NOK Company [9] collaborated to successfully develop a one-step gas-phase synthesis process (the AIST process) that uses palladium as a catalyst for the direct oxidation of benzene to phenol. This process uses a reactor composed of a stainless steel outer tube and a porous α-alumina inner tube; the key component is a palladium membrane catalyst with a thickness of 1 μm, which is coated on the outside of the alumina tube using chemical vapor deposition. This membrane was developed jointly by AIST, Maruzen Petrochemical Company, and NOK Company. The reactor is placed in a heating furnace heated to 150–250°C; benzene and oxygen flow through the alumina inner tube, while hydrogen at a pressure of 0.2 MPa passes along the outside of the tube. Hydrogen is adsorbed on the membrane, where it is dissociated and activated. It then passes through the inner surface of the alumina tube, where it captures oxygen molecules on the inner surface of the activated hydrogen capture tube, thereby generating activated oxygen. This activated oxygen undergoes an addition reaction with benzene rings to form benzene epoxides, which are subsequently isomerized to produce phenol. In the laboratory, when the conversion rate is below 3%, the selectivity for phenol production is greater than 90%. When the conversion rate is 10%–15%, the selectivity for phenol production is greater than 80%. The phenol yield (per 1 kg of catalyst) is 1.5 kg/h, and the conversion rate is expected to increase further with improvements in the process. This synthesis method does not require large-scale equipment; simply increasing the number of small reaction tubes is sufficient to scale up the process ； Furthermore, since no propylene is produced as a by-product, the synthesis process is greatly simplified, and energy costs are **reduced**. In addition to being used for the synthesis of benzene ring products such as phenol, this method can also be applied to the oxidation reactions of aromatic compounds such as naphthalene and pyridine rings. Recently, Nippon Daisel Chemical Industry Co., Ltd. and Kansai University in Japan jointly developed a high-yield one-step process for the direct oxidation of pure benzene and carbon monoxide to produce phenol [10]. This process uses a homogeneous heteropolyacid containing molybdenum and vanadium (i.e., molybdenum-vanadium phosphate) as the oxidation catalyst. Benzene reacts in a mixed solvent of acetic acid and water under pressurized conditions of carbon monoxide and air (1.0–1.5 MPa), with the reaction temperature controlled at 90°C. Under laboratory conditions, the selectivity for phenol is over 90%, and the yield of phenol can reach 20%–30%, which is higher than that of other similar processes using metal complexes such as Pd as catalysts; the catalyst can be regenerated and reused. The company is working with large phenol producers to conduct industrial trials of this process. 3 Oxidation process using H2O2 as an oxidant: The traditional process for producing phenol via H2O2 oxidation employs TS-1 or Ti-MCM-41 catalysts. Due to its larger pores, Ti-MCM-41 exhibits better catalytic activity, with a selectivity of over 95%. However, this reaction requires the use of acetonitrile, which is highly toxic, which hinders the industrial application of this technology. EniChem Chemical Company [11] has conducted long-term research on the oxidation of benzene to phenol using H2O2 as an oxidant. Initially, it was a liquid-phase reaction; the catalyst consisted of titanosilicate pre-activated with H2O2 and fluoride ions. The reaction temperature was 80°C and the reaction time was 2 hours, with a benzene conversion rate of 6%–7%. The selectivity for phenol based on benzene was 97%–100%. The company [12] has also recently developed a production process for synthesizing phenol directly from benzene, using H2O2 as an oxidant in a biphasic reaction solvent system. The organic phase consists of the starting material benzene and an organic solvent (preferably acetonitrile), while the aqueous phase is composed of H2O2 and a catalyst. The catalytic system consists of nitrogen-containing heteroaromatic carboxylic acid ligands, inorganic or organic acidic solvents, and Fe2+ or Fe3+ salts. The optimal catalytic system composition is: 0.03 mmol of FeSO4·7H2O, 0.1 mmol of 5-methyl-pyrazine-2-carboxylic acid, 0.07 mmol of trifluoroacetic acid, and 6.45 mL of water. 18.6 mol of benzene and 9.16 mL of acetonitrile were combined with this catalytic system, and 0.22 mL of 30% H2O2 was added at the beginning of the reaction. Heat the reaction mixture to 70°C and heat for 10 min. Under the action of this catalytic system, the conversion rate of H2O2 was 93%, the selectivity for producing phenol from H2O2 was 86%, the conversion rate of benzene was 8%, and the selectivity for producing phenol from benzene was 96%. Due to its presence in a two-phase solvent system, the synthesis of phenol exhibits high selectivity. Once formed in the aqueous phase, phenol can immediately penetrate into the organic phase, preventing further oxidation of phenol. The Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences [13] has developed a method for directly hydroxylating benzene to produce phenol. It is characterized by a two-phase system composed of water and water-insoluble ionic liquids, using a dodecylsulfonate of a transition metal as a catalyst and 30% H2O2 as an oxidant. Among them, the dodecylsulfonate catalyst of transition metals and the reactant benzene are soluble in the ionic liquid phase but insoluble in the aqueous phase, while the oxidant H2O2 and the product phenol are soluble in the aqueous phase but insoluble in the ionic liquid phase (the ionic liquid being 1-alkyl-3-methylimidazolium tetrafluoroborate or 1-alkyl-3-methylimidazolium hexafluorophosphate). The molar ratio of catalyst to benzene is 0.4–1:225, the molar ratio of benzene to H2O2 is 1:1–2, and the volume ratio of the ionic liquid phase to the water phase is 1:2–550. In this two-phase reaction system, the reaction is carried out under stirring at temperatures of 30–70°C for 4–8 hours, during which benzene is oxidized to phenol with high selectivity. This water/ionic liquid two-phase system features high conversion rates, easy separation of the product phenol, and reusability, offering good prospects for industrial application. The Dalian Institute of Chemical Physics, Chinese Academy of Sciences [14] used modified natural red clay as a carrier, metal oxides (oxides of vanadium, manganese, copper, etc.) as active components in the catalyst, and H2O2 as an oxidant for the hydroxylation of benzene to produce phenol. The conversion rate of benzene is greater than 5%, and the selectivity for phenol is greater than 80%. Shi Xiaobo and others from the Department of Chemistry at Zhanjiang Normal University [15] synthesized four types of nanometal phosphomolybdovanadate heteropoly acids with the general formula H3MPMo10V2O40XH2O (M=Co2+, Ni2+, Cu2+, Zn2+) using a room-temperature solid-state reaction method. The effects of factors such as the H2O2/C6H6 molar ratio, reaction medium, reaction temperature, and reaction time on the activity of the nanocatalysts in the hydroxylation of benzene were investigated. The results showed that the four transition metal phosphomolybdovanadate nanocatalysts exhibited excellent catalytic activity for the hydroxylation of benzene to produce phenol. Under conditions of a H2O2/benzene molar ratio of 1.5:1, a mass ratio of benzene to catalyst of 25:1, water as the solvent, a reaction time of 2 hours, and a reaction temperature of 70°C, the yield of phenol was greater than 50% with a selectivity of over 98%. Xiaodong et al. [17] from Beijing Yanshan Petrochemical Company used a self-developed TS-1 molecular sieve, and applied the uniform design method to comprehensively optimize the reaction conditions for the one-step hydroxylation of benzene to produce phenol. Under conditions of a reaction temperature of 75°C, a catalyst dosage of 2.2 g/mol, a molar ratio of n(benzene)/n(H2O2) of 10/1, and a concentration of H2O2 of 0.52 mol/L, the reaction was carried out for 2 hours; the conversion rate of benzene was 6.18%, while the conversion rate and utilization efficiency of H2O2 were 87.4% and 89.2%, respectively. Chen Jing and others from the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences [18] studied the use of a catalyst system composed of polyhydroxyl compounds such as diprotic acids and pyrodiprotic acids together with Fe(II) in the reaction of oxidizing benzene with H2O2 to produce phenol. At a reaction temperature of 80°C, the conversion rate of benzene was 82.2% in the diprotic acid catalyst system, the selectivity for phenol was 85.5%, and the effective conversion rate of H2O2 was 48.3%. Fu Zhenjin and others from Sichuan University [19] introduced three other metal elements as components alongside Ni to create a series of catalysts, and investigated the reaction activity of the direct oxidation of benzene to phenol using these catalysts. The results showed that using a Ni/γ-Al2O3 catalyst, with 25 mL of benzene, 50 mL of ammonia water, 10 mL of hydrogen peroxide, and 1 g of catalyst in the reaction system, and after a reaction time of 4.5 hours, 43.24 mg of phenol was obtained. 4 Conclusion From the perspectives of atom economy and green chemistry, the development of a process for the direct hydroxylation of benzene to phenol is of great significance. The prominent advantage of direct oxidation of O2 to phenol is the low cost of O2, but the yield is too low, leaving a long way to go before it can meet the requirements for industrial application. Using H2O2 as an oxidant allows for a wide range of catalysts to be employed, resulting in high yields and selectivity. With the development of new catalysts and cost-effective processes for synthesizing H2O2, as well as advances in in-situ synthesis techniques, this process holds great potential for industrial application. The synthesis of phenol via gas-phase reactions using N2O as an oxidant requires high reaction temperatures and incurs high costs; however, the yield and selectivity of phenol obtained in this method are significantly better than those achieved with the other two types of oxidants. If N2O can be obtained cheaply as a by-product in fatty acid production, then this process would have cost advantages and hold great potential for development