Liquid Phase Air Oxidation Research Articles

Noncatalytic Liquid Phase Air Oxidation of Ethylbenzene to 1-Phenyl Ethyl Hydroperoxide in Low Oxygen Volume Fraction

The catalyst- and solvent-free liquid phase air oxidation reaction of ethylbenzene (EB) to 1-phenyl ethyl hydroperoxide (PEHP) was investigated at scheduled temperature and pressure with a separate deacidifying zone. The oxidation reaction was done in the titanium fabricated reactor at an oxygen volume fraction in the outlet gas less than 0.3%. The effects of several reaction parameters were studied in detail. In the optimal reaction conditions and instructions given in this work, the high selectivity to PEHP (above 95%) was achieved with EB conversion around 13%, and a clean feed (water and acid-free) was provided for the propene epoxidation reaction.

Synthesis of 2,5-furandicarboxylic acid by the aerobic oxidation of 5-hydroxymethyl furfural over supported metal catalysts

Supported Pt catalysts are synthesized, characterized and are used in the liquid phase air oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). Under the optimum reaction conditions of a stepwise increase in the reaction temperature (75 and 140 °C for 12 h each), we achieved as high as 96 % FDCA yield in presence of 1 bar oxygen pressure over Pt/γ-Al2O3. It is shown that as the oxygen pressure increases (1–10 bar), the FDCA yields decrease, since at higher partial pressure of oxygen, overoxidation reactions of substrate and product(s) are possible. It is interesting to note that even with air as an oxidant, we obtained similar yields of FDCA as that with oxygen. Moreover, the effects of base (weak or strong), its concentration (equimolar or excess) were studied in detail. It is important to increase the reaction temperature in a stepwise manner to achieve higher yields of FDCA since at higher temperatures HMF undergoes self-degradation and thus the yields of FDCA decrease. The self-degradation of HMF is also proved by undertaking the reaction under nitrogen environment. The study on the effect of substrate-to-catalyst ratio is done to improve up on the economics of overall process. The effect of supports (reducible and non-reducible) and their oxygen storage capacity is discussed and is proposed to be one of the factors to change the course of reaction. Furthermore, we have shown that FDCA formed in the reaction can be successfully isolated (91 %, isolated yield) in the pure form and its purity is confirmed by NMR, melting point, and elemental analysis. The catalysts were characterized with X-ray powder diffraction, transmission electron microscopy and inductively coupled plasma-optical emission spectroscopy techniques.

Catalytic Oxidative Desulfurization of Diesel Fuels Using Air in a Two-Step Approach

This study presents a novel approach to fuel desulfurization in two steps where air is used as oxidant for the in situ generation of hydroperoxides from aromatics in diesel fuel and then the sulfur compounds are oxidized by the hydroperoxides to sulfones. Bulk and supported CuO based catalysts were examined for oxidation of surrogate and real diesel fuels for generation of hydroperoxides in situ using air. Among bulk CuO, CuO/Al2O3, CuO/SiO2, CuO/TiO2, and CuO-ZnO/Al2O3 tested, CuO/Al2O3 gave the highest conversion, but the highest yield and selectivity for hydroperoxide was obtained on bulk CuO catalyst for liquid phase air oxidation of isopropylbenzene. H2-Temperature programmed reduction (H2-TPR) revealed the presence of dispersed CuO phase on supported catalysts with bulk CuO as the dominant phase on the unsupported catalyst. Three real diesel fuels were tested for liquid phase air oxidation at 120 °C in the presence of bulk CuO catalyst which revealed different levels of hydroperoxides generation. Th...

Preparation of Polycarboxylic Acids by Oxidative Cleavage with Oxygen / Co-Mn-Br System

Adipic acid and glutaric acid were obtained from 1-hydroxy-2- acetoxycyclohexane by oxidation cleavage using molecular oxygen in the presence of cobalt acetate, manganese acetate and hydrobromic acid in acetic acid solution. Applying this method to prepare dicarboxylic acids from unsaturated fatty acids, we proposed an efficient method where reaction mixture of unsaturated fatty acids and hydrogen peroxide - formic acid can be oxidative cleaved to produce dicarboxylic acids and monocarboxylic acids in acetic acid solution with molecular oxygen / Co-Mn-Br system. For example, azelaic acid, suberic acid and other dicarboxylic acid as dicarboxylic acids were obtained from industrial oleic acid, which contained oleic acid, palmitoleic acid, linoleic acid, and linolenic acid. As a result of investigation for reaction condition, increase of partial pressure of molecular oxygen or elevation of temperature accelerated oxidative cleavage, but total yields of azelaic acid and suberic acid were slightly decreased. Besides, effect of hydrohalic acids in liquid phase air oxidation in the presence of cobalt and manganese acetates was investigated to show that HBr was the most effective. Soybean acid and tall acid containing higher amounts of linoleic acid and linolenic acid than industrial oleic acid were also oxidatively cleaved to dicarboxylic acids.

Αn efficient γ-Fe2O3 catalyst for liquid phase air oxidation of p-hydroxybenzyl alcohol under mild conditions

Abstract γ-Fe 2 O 3 (maghemite) particles were synthesized at 5 °C (LT, low temperature) and 95 °C (HT, high temperature) using a simple chemical protocol. The major reflection in XRD was observed to be of the γ-Fe 2 O 3 phase which was further supported by the XPS analysis. Fe 3+ species were responsible for initiation of the oxidation of p -hydroxybenzyl alcohol. SEM revealed that the morphologies of the catalysts were different for samples prepared at two different temperatures. γ-Fe 2 O 3 (LT) showed the highest catalyst activity (84% conversion) for liquid phase air oxidation of p -hydroxybenzyl alcohol with 94% selectivity to the oxidation products at 370 K and ambient pressure conditions.

Highly Active Nanostructured Co3O4 Catalyst with Tunable Selectivity for Liquid Phase Air Oxidation of p-Cresol

Abstract This is a first report of highly efficient heterogeneous nanostructured Co3O4 catalyst (6–8 nm) having high surface area (95 m2/g) developed for selective liquid phase air oxidation of p-cresol under atmospheric pressure conditions.

Reaction kinetics of liquid phase air oxidation of p-cresol to p-hydroxybenzaldehyde

Abstract The kinetics of liquid phase oxidation of p -cresol to p -hydroxybenzaldehyde has been investigated using insoluble cobalt oxide (Co 3 O 4 ) catalyst at oxygen partial pressures in the range 0.1–1.5 MPa, reaction temperatures 333–393 K, p -cresol concentrations 0.49–1.53 kmol/m 3 and catalyst loadings 0.38–3.03 kg/m 3 . The effects of oxygen partial pressure, reaction temperature, p -cresol concentration and catalyst loading on the initial rate of reaction have been studied. The initial rate varied linearly with catalyst loading up to 1.5 kg/m 3 beyond which it was independent of the catalyst loading while first-order dependence was observed with variation in oxygen partial pressure. A rate expression has been proposed considering Langmuir–Hinshelwood (LH) type mechanism, based on the initial rate data. A batch reactor model was also developed based on the kinetics studied and the concentration time profile predicted by the model was in good agreement with the experimental data. The activation energy for the liquid phase oxidation of p -cresol was found to be 39.6 kJ/mol.

Carbon coated monolithic catalysts in the selective oxidation of cyclohexanone

The application of carbon coated monolithic catalysts in selective oxidation is compared with slurry phase operation. As a model reaction, the liquid phase air oxidation of cyclohexanone into adipic acid was chosen. The reaction was performed in water at moderate temperature (413K) and pressure (5.0MPa). Total conversion of cyclohexanone was achieved over metal-free carbon supports yielding several dicarboxylic acids. Increasing the pore access of these carbon supports is beneficial for the activity. The application of highly dispersed platinum yields similar activities, but enhances the selectivity to adipic acid from 9.2 to 20.6%.

Studies on the Synthesis of Aromatic Tetracarboxylic Acid (Part 1)

A method for synthesizing pyromellitic acid by liquid phase air oxidation of durene was studied. The air oxidation of durene was carried out in glacial acetic acid, using Co(OAc)2•4H2O, Mn(OAc)2•4H2O and KBr as catalysts, at the reaction temperature of 205-210°C and the total pressure of 20kg/cm2•G. The solid materials obtained by the oxidation were recrystallized into pyromellitic acid in an aqueous solution of nitric acid. The following results were obtained.(1) Cobalt and manganese used as catalysts were found, after oxidation, as salts in the solid material and had to be removed by treating with mineral acid to obtain pyromellitic acid.(2) The oxidation of durene into pyromellitic acid required a far larger amount of catalysts than the oxidation of p-xylene into terephthalic acid.(3) In the presence of heavy metal component, bromine component in the catalysts accelerated the latter stage of the oxidation, thereby promoting the formation of pyromellitic acid.(4) Bromine component in the catalysts suppressed the deactivation of heavy metal caused by the oxidation product.(5) Pyromellitic acid was produced from durene with the maximum yield of about 90mol%.

The Liquid Phase Air Oxidation of 1-Butanol

The liquid phase air oxidation of 1-butanol at 15-100C in the presence or absence of six catalysts (manganese naphthenate, ferrous naphthenate, stannic acetate, dupric acetate, cobalt acetate, and chromium acetate), using acetaldehyde as a reaction initiator, was attempted and the influences of the reaction conditions on the yields of products or the conversion to products were investigated. By this oxidation, n-butyraldehyde and butyric acid were produced and nbutyl acetate was obtained as a by-product. Among six catalysts, manganese naphthenate and ferrous naphthenate were not active catalysts, while cobalt acetate and chromium acetate were found to catalyze the oxidation of 1-butano1. Under the optimum condition in the presence of chromium acetate, 72% of 1-butanol was converted to 2% of n-butyraldehyde, 67% of butyric acid, and 3% of n-butyl acetate. The liquid phase air oxidation of 1-butanol in the presenee of chromium acetate catalyst was investigated kinetically and this oxidation was found to be a simultaneous reaction resulting from the esterifieation of 1-butanol and a consecutive oxidations ef 1-butanol to 1-butyraldehyde and of 1-butyraldehyde to butyric acid. The rates of these reactions were found to be expressed by a first order equations of corresponding reactants.The rate constants of these reactions were in the range from 10-2 to 1(hr-1) and the activation energies were less than 10 kcal/mol.

One-Step Synthesis of Propylene Oxide from Propylene VII.

Liquid phase air oxidation of propylene to propylene oxide (PO) was studied inbenzene in the presence of metal phthalocyanine (Me-Pc) catalysts. The resultsare as follows ;(1) The effects of reaction variables on the rate of reaction and PO selectivity with Me-Pc catalysts were much similar to those with Mn-naphthenate (Mn-N) catalyst. Most of the Me-Pc catalysts tested, however, gave somewhat higher PO selectivities. It may be reasonably explained by the Kropf's mechanism of the activaton of oxygen by Me-Pc catalysts .[Ann. 631 73 (1960)].(2) The activity of various Me-Pc catalysts for PO formation at 175°C decreased in the following order. Co-Pc≅Ni-Pc>Ag-Pc≅Cu-Pc≅Na-Pc≅Mn-Pc>Zn-Pc≅Ti-Pc≅no catalyst ≅Mn-N>>Li-Pc

Active Form of the Catalyst for the Liquid Phase Air Oxidation of Hydrocarbons

In the liquid phase air oxidation of hydrocarbons catalyzed by metal salts, an active catalyst is formed at the end of the induction period. In order to clarify this active catalyst, catalytic activities for the oxidation of m-xylene, and Rf values of paper chromatography were compared for several green colored cobalt catalysts of different sources. One of the catalysts was withdrawn from an oxidation reaction system of xylene catalyzed by cobaltous salt. The others were prepared by two methods: 1) reaction of cobaltous salt with hydrogen peroxide or hydroperoxide in the presence of aromatic acid and 2) reaction of cobaltous salt with benzaldehyde or perbenzoic acid.Rf values of paper chromatography were identical with these green cobalt catalysts which were different from the cobaltous salt employed as their starting materials. When these catalysts were used in the oxidation of m-xylene, the induction period was extremely shortened, which is not the case with untreated cobaltous salt.A further investigation; i.e., elementary analysis, conductometric titration and iodometry, on cobaltous adipate, cobaltous caprate and pure green catalysts prepared from these salts, indicated that the green catalyst consisted of Co2(A)3(OH)2 unit containing Co(II) and Co(III) in the ratio of 1:1.

The Effect of Catalyst Containing Bromine in Liquid Phase Air Oxidation I

The liquid phase oxidation of p-xylene was carried out in the presence or absence of solvents (fatty acids) using cobaltous stearate, organic bromine compounds, hydrogen bromide and their mixtures as catalyst. The reaction temperature and the oxygen partial pressure were varied in the range of 130∼230°C and 1∼16atm., respectively. p-Toluic acid was also oxidized in the same manner in di-tert-butyl benzene. The following results were obtained.1) By use of bromine compounds other than hydrogen bromide as catalyst, p-xylene always yielded larger amount of p-toluic acid than p-tolualdehyde. However, aldehyde predominated when hydrogen bromide was used as catalyst and the yield of aldehyde increased with an increase in the concentration of hydrogen bromide.2) In the case of p-xylene oxidation in the fatty acid solvent, the yield of aldehyde using bromine compounds with cobaltous salt as catalyst was higher than when using cobaltous salt alone. It seems, therefore, that hydrogen bromide participates to some extent in this reaction.3) In the cases of p-xylene oxidation in the acidic solvent and p-toluic acid oxidation in inert solvent under the condition of high temperatures and high pressures, synergism of cobaltous salt with bromine compounds was noticed.4) It is concluded from the above that an addition of bromine compounds in the reaction mixture is more effective to the toluic acid→terephthalic acid stage than to the xylene→toluic acid stage.

プロピレンの液相加圧空気酸化における諸反応因子と反応速度との関係

プロピレンの液相加圧空気酸化における諸反応因子と反応速度との関係

Effects of Catalyst son the Lower Fatty Acids Formation Reactions by the Liquid Phase Air Oxidation of Petroleum Hydrocarbons

In order to investigate the effect of catalyst on liquid phase air oxidation of petroleum hydrocarbons in the preparation of lower fatty acids, the authors studied the oxidation of petroleum naphtha at 160°C, 40atm, in the presence of Na, Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Cd, Sn, Ba, Ce, Pb, or Bi Catalyst (used as salt of naphthenic acid or octylic acid), and observed the following results.1. Compared with non-catalytic reaction, the induction periods were shortened by the salts of metals which belonged subgroup a in periodic table, and prolonged by the salts of metals which belonged subgroup b.2. Manganese salt was the only catalyst which increased the ratio of (secondary oxidation of intermediate products)/(primary oxidation of hydrocarbons). The addition of V or Cd salt was apt to suspend reaction.3. The yield of formic acid was in the order of Mn>none>Co. The yield of acetic acid was in the order of Mn, Cu>none>Na, Co, Ni, Zn, Sn, Bi, Pb. The ratio of acetic acid to formic acid was in the order of Co>none>Mn.These phenomena were observed regardless of the types of raw hydrocarbons-paraffinic or naphthenic-, and the types of anion component of catalyst-naphthenic acid or octylic acid-.

The Effect of Catalyst Containing Bromine in Liquid Phase Air Oxidation II

The Effect of Catalyst Containing Bromine in Liquid Phase Air Oxidation II

Studies on the Separation of Pure Succinic Acid from the Crystal Produced by the Liquid Phase Air Oxidation of Petroleum Naphtha

Studies on the Separation of Pure Succinic Acid from the Crystal Produced by the Liquid Phase Air Oxidation of Petroleum Naphtha

Liquid Phase Oxidation of Xylenes and Toluic Acids with Oxygen, and Inhibitory Effect of Organic Acids on the Oxidation

Reactivities of xylenes in the liquid phase air oxidation at 135°c with cobalt naphthenate catalyst was in order of o->m-≅p-xylene. The velocity of oxidation with cobalt bromide catalyst without solvent in a stationary chainpropagation period was in the order of o-<in-≅p-xylene. The presence of bromine in cobalt catalyst increased the oxidation velocity in the propagation period (with the exception of o-xylene, no solvent system in which the oxidation was decreased). The ratio of the reaction velocity coefficient, k2/k1, in the twostep oxidation of xylenes toluic acids benzenedicaroxylic acids was not much dependent on the kind of xylenes in case of using cobalt naphthenate catalyst. The ratio k2/k1 became smaller with cobalt bromide catalyst than with cobalt naphthenate catalyst. In the liquid phase oxidation of toluic acids at 150°c to benzenedicarboxylic acids, it was found that the reaction was proceeded smoothly in case of m-or p-toluic acids but not in case of o-toluic acid. This may be attributed mainly to inactivation of catalyst by the o-phthalic acid. This kind of inactivation is found commonly in organic acids having a large dissociation constant and was found in case of oxidation of easily oxidizable xylenes too, though the tendency is smoll.

Mixing Effect of Raw Materials on the Liquid Phase Air Oxidation of Hydrocarbons

Mixing Effect of Raw Materials on the Liquid Phase Air Oxidation of Hydrocarbons

Effects of the Raw Material Compositions on the Liquid Phase Air Oxidation of Petroleum Naphthas

For the purpose of preparing lower fatty acids, various kinds of petroleum naphthas were air oxidized for 6hr. after induction period on the liquid phase under 40atm, at 160°C, with manganese naphthenate catalyst, and following results were obtained.(1) In the oxidation of petroleum naphthas, the oxidation speed of component hydrocarbons were about the same and the total yields of formic acid plus acetic acid were much higher than the values expected from the experiment when each component hydrocarbons were oxidized independently.(2) The amount of absorbed oxygen increased with increasing iso-structures of petroleum naphthas. When the quantities of iso-structures were the same, naphthenic naphthas absorbed more oxygen than paraffinic naphthas.(3) Generally higher yields of formic acid plus acetic acid were obtained from low b.p. range ( 100°C) naphthas. In the low b.p. range naphthas, the yields were about the same whether these were paraffinic or naphthenic, however in the high b.p. range naphthas higher yields were obtained from naphthenic than paraffinic.(4) In the low b.p. range naphthas, the ratios of (acetic acid)/(formic acid) were higher from paraffinic naphthas than from naphthenic naphthas, however in the high b.p. range naphthas the ratios were equal or slightly higher for naphthenic than paraffinic.