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A kind of method that toluene and trioxane prepare styrene

A technology of paraformaldehyde and styrene, applied in the chemical industry, can solve problems such as hindering development and application, methanol decomposition, etc., achieve the effects of inhibiting the production of ethylbenzene, increasing the ratio of styrene/ethylbenzene, and facilitating large-scale industrial production

Active Publication Date: 2021-03-02
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, severe methanol decomposition during the side-chain alkylation of toluene and methanol and the easy hydrogen transfer reaction between styrene and methanol to form ethylbenzene in the product hinder the further development and application of this process technology.

Method used

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  • A kind of method that toluene and trioxane prepare styrene
  • A kind of method that toluene and trioxane prepare styrene
  • A kind of method that toluene and trioxane prepare styrene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] The preparation of embodiment 1 supported phosphoric acid catalyst

[0057] The carrier to be impregnated was calcined at 500° C. for 6 h in an air atmosphere, and then cooled to room temperature. 50 g of the calcined carrier was weighed, and an equal volume of impregnated with phosphoric acid aqueous solution was added. After immersing at room temperature for 12 hours, the resulting mixture was dried at 110°C, and then heated to 550°C for 4 hours in an air atmosphere at 10°C / min. 40 mesh spare. The oxide supports and phosphoric acid loadings used in different samples are shown in Table 1.

[0058] Table 1

[0059] sample carrier load (mass) PH-1 #

Embodiment 2

[0060] The preparation of embodiment 2 basic molecular sieve catalysts

[0061] The carriers of the basic molecular sieves used in the examples were purchased commercially.

[0062] Take 80 g of molecular sieves such as NaX (Si / Al=1.17), NaY (Si / Al=2.89), Naβ (Si / Al=4.61), and divide them into several parts according to the mass, and then use 0.3mol / L KNO 3 , RbNO 3 , CsNO 3 Wait for 120ml of different precursor solutions, exchange 2-4 times at 80°C, filter and wash, then dry at 110°C, roast in air at 550°C for 4 hours, grind, press, crush and sieve into 20-40 mesh Standby, the obtained samples are respectively marked as Z-1 # , Z-2 # , Z-3 # , Z-4 # , Z-5 # , Z-6 # , Z-7 # , Z-8 # .

[0063] The obtained sample number, ion exchange liquid type, concentration, exchange frequency and ion exchange degree are shown in Table 2. The elemental analysis of the obtained sample was carried out by XRF elemental analysis, and the degree of ion exchange was calculated accordin...

Embodiment 3

[0068] Embodiment 3 catalyst evaluation

[0069] In the prepared supported phosphoric acid catalyst PH-1 # ~PH-8 # Select a sample, and at the same time in the prepared basic molecular sieve catalyst Z-1 # ~Z-8 # One sample was selected, and then 1 g of the selected sample was loaded in the upper and middle parts of the small fixed-bed reactor in turn, and quartz sand was filled at both ends of the reactor and between the two catalyst beds.

[0070] Table 3 shows the numbers of the supported phosphoric acid catalyst samples and the numbers of the basic molecular sieve catalyst samples selected for the sample combination of each experiment.

[0071] table 3

[0072]

[0073]

[0074] After filling the reactor, the two catalyst beds were first activated under nitrogen atmosphere (40ml / min) at 380°C and 550°C for 1h respectively, and then cooled down to the reaction temperature, and the raw materials toluene and paraformaldehyde were fed in with a micro feed pump , Tol...

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Abstract

The invention discloses a method for preparing styrene from toluene and paraformaldehyde, which at least includes the following steps: feeding raw material gas containing toluene and paraformaldehyde into a reactor, first contacting with catalyst I to depolymerize the paraformaldehyde into formaldehyde , and the obtained mixed gas is contacted with catalyst II to carry out side chain alkylation reaction to prepare styrene. The method can effectively avoid the hydrogen transfer reaction between styrene and methanol when methanol is used as the alkylating agent by replacing methanol with the formaldehyde produced by the depolymerization of paraformaldehyde as the side chain alkylating agent, and improve the styrene / methanol ratio in the product. It has the characteristics of high conversion rate of toluene and high selectivity of styrene in the product.

Description

technical field [0001] The invention relates to a method for preparing styrene from toluene and paraformaldehyde, which belongs to the field of chemical industry. Background technique [0002] Styrene (ST), as the most basic aromatic chemical, is the most used chemical product among benzene derivatives, and can be used to manufacture polystyrene (PS), expanded polystyrene (EPS), acrylonitrile-butanediene Various downstream chemical products such as ethylene-styrene resin (ABS), styrene-butadiene rubber (SBR) and so on. At present, the mainstream technology for industrial production of styrene is the dehydrogenation of ethylbenzene, which includes two steps of alkylation of benzene and ethylene to produce ethylbenzene and dehydrogenation of ethylbenzene to produce styrene. Due to the problems of long process flow, many side reactions, high energy consumption and excessive dependence on petroleum resources in ethylbenzene dehydrogenation, the development of new styrene produc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C1/20C07C15/46B01J27/18B01J27/182B01J29/08B01J29/70
Inventor 徐力许磊李沛东韩乔袁扬扬
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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