Toluene methylation process

A technology of toluene methyl and toluene, applied in chemical instruments and methods, catalysts, organic chemistry, etc., can solve problems such as activity reduction

Inactive Publication Date: 2006-05-24
SAUDI BASIC IND CORP SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The catalyst showed a selectivity of up to 97% to p-xylene, however, the catalyst showed a decrease in its activity within hours due to coke deposition

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] 2.70 ml of catalyst was loaded into the reactor. The catalyst was dried at a temperature of 200° C. under a flow of hydrogen for at least 1 hour before feeding. Reactor pressure was maintained at 20 psig. at about 32hr -1 A premixed toluene / methanol feed with a molar ratio of 1 / 1 was added at a rate of about 1.445 ml / min at a LHSV of . co-feed hydrogen at a rate of 50cc / min to give H 2 The / HC molar ratio is about 0.1. The catalyst bed inlet temperature was slowly increased (10°C / min) and adjusted to about 600°C. After 1 hour from initial airflow, adjust operating conditions to run conditions. Feed rate reduced to about 0.089ml / min to give LHSV about 2hr -1 . Also, the rate of hydrogen as a co-feed was increased from 50cc / min to 223cc / min to reduce the H 2 The / HC molar ratio was kept at about 7. The reaction start-up conditions and operating conditions, as well as toluene conversion and p-xylene selectivity are listed in Tables 1A and 1B.

[0032] ...

Embodiment 2

[0036] 2.70 ml of catalyst was loaded into the reactor and the catalyst was dried at 200°C under hydrogen flow for at least 1 hour before feeding, and the reactor pressure was maintained at 20 psig. Introduce molar ratio 2 / 1 pair premixed toluene / methanol feed at about 0.101ml / min, LHSV about 2hr -1 . Hydrogen as a co-feed in H 2 The / HC molar ratio is about 1.6 and is introduced at a speed of 51cc / min. The catalyst bed inlet temperature is slowly increased (10°C / min) and adjusted to 600°C. 2 A / HC molar ratio of 7.8 increases the co-feed hydrogen rate from 51 cc / min to 223 cc / min. After 99 hours of stream, in H 2 The hydrogen co-feed rate was further reduced from 223 cc / min to 51 cc / min at a / HC molar ratio of about 1.7. By adding H 2 The conversion of toluene was improved when the / HC molar ratio was decreased from about 7.8 to 1.7. The start-up and normal operating conditions of the reactor, as well as toluene conversion and p-xylene selectivity are described in Table...

Embodiment 3

[0041] 1.40 ml of catalyst was loaded into the reactor and the catalyst was dried at a temperature of 200° C. in a stream of hydrogen for at least 1 hour prior to feeding, and the reactor pressure was maintained at about 20 psig. A feed of toluene / methanol premixed at a molar ratio of 2 / 1 was introduced at a rate of about 0.182ml / min with a LHSV of about 8hr -1 . Co-feed hydrogen at 471 cc / min to give H 2 The / HC molar ratio is about 8.0. The catalyst bed inlet temperature was slowly increased (10°C / min) and adjusted to about 500°C. The operating conditions of the reactor, as well as toluene conversion and p-xylene selectivity are described in Tables 3A and 3B.

[0042] Initial conditions

[0043] Flow time, hours

[0044] from figure 1 with 2 It can also be seen in Example 3 that the selectivity to p-xylene in Example 3 was approximately 90% during the 139 hour reaction run, while the initial conversion was approximately 2%. Data recorded during s...

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PUM

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Abstract

A process for preparing xylene in a reactor containing phosphorus-treated ZSM-5-type catalyst. The process involves initially initiating the toluene methylation reaction by contacting the catalyst with a toluene / methanol feed and, under certain conditions, hydrogen introduced into the reactor as a co-feed. By utilizing start-up conditions, high selectivity to p-xylene can be achieved while maintaining stable catalytic activity over a considerable period of time.

Description

technical field [0001] This invention generally relates to the alkylation of aromatic compounds. Background technique [0002] Para-xylene is an important substituted aromatic compound due to the high demand for its oxidation to terephthalic acid, a major component in the formation of polyester fibers and resins. Para-xylene can be produced commercially by naphtha hydrotreating (catalytic reforming), naphtha or gasoline steam cracking, and toluene disproportionation. [0003] Alkylation of toluene with methanol, a known method of toluene methylation, has been used in laboratory studies to produce paraxylene products. Toluene methylation is known to take place over acidic catalysts, especially zeolites or zeolite-type catalysts. In particular, ZSM-5-type zeolites, zeolite beta and silicoaluminophosphate (SAPO) catalysts have been used in this process. In general, a thermodynamic equilibrium mixture of ortho (o)-, meta (m)-, and p-xylenes can be formed by methylation of tol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C1/22B01J29/40C07C2/66C07C2/86
CPCC07C2/864C07C2529/40Y02P20/52C07C15/08C07C2/66
Inventor A·K·高希P·哈维
Owner SAUDI BASIC IND CORP SA
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