Process for the manufacture of catalysts used for producing para-xylene by toluene shape selective alkylation
The present invention relates to a process for the manufacture of catalysts used for producing para-xylene by toluene shape selective alkylation. The invention is primarily used for solving the problems in the old technology, e.g., high requirements on the environment and great treatment of waste water containing organic amines when synthesizing ZSM-5 molecular sieves by using an organic amine as the template agent; small and non-homogeneous particles of the molecular sieves when synthesizing ZSM-5 molecular sieves by using an alcohol or ether as the template agent, such that the catalyst prepared thereby has low catalytic selectivity and low toluene conversion rate, etc. Said problems are better solved in the present invention by synthesizing ZSM-5 molecular sieves using the combination of organic amines and alcohols or ethers as the template agents (having a weight ratio of organic amines/alcohols=0.05-150, and organic amines/ethers=0.05-150), and modifying with organosilicon so as to obtain the catalysts. Said catalysts can be used in the industrial production of para-xylene manufactured by toluene shape selective alkylation.
1. A process for the manufacture of catalysts used for producing para-xylene by toluene shape selective alkylation, comprising the steps of
e) using silica sol, water glass or sodium silicate as a silica source, aluminium sulphate, sodium meta-aluminate or aluminates as an alumina source, and mixture of organic amine and alcohol or ether in a weight ratio of organic amine/alcohol or ether of 0.05-150 as a template agent to form a synthesis mixture having a molar ratio of SiO 2 /Al 2 O 3 =20-200, H 2 O/SiO 2 =30-140, NH 3 /Al 2 O 3 =1-100, Na 2 O/Al 2 O 3 =0-18, hydrothermally-crystallizing the synthesis mixture at 120-200° C. for 10-200 hours to obtain the liquid product containing ZSM-5 molecular sieves;
f) filtering and washing said liquid product containing ZSM-5 molecular sieves from step a), and converting the molecular sieves to NH 4 -type ZSM-5 molecular sieves by ion exchange;
g) adding at least one kneading agent selected from the group consisting of silica sol, aqueous organosilicon, silica gel and titanium white to NH 4 -type ZSM-5 molecular sieves from said step b), shaping, drying and calcining to obtain a catalyst matrix; and
h) modifying the catalyst matrix with at least one organosilicon selected from the group consisting of phenylmethylpolysiloxane, hydroxyl silicone oil, amino silicon oil and dimethyl silicon oil so as to support organosilicon on the surface of the molecular sieves, calcining at 300-600° C. for 0.5-12 hours, converting organosilicon to inorganic silicon to obtain a catalyst used for producing para-xylene by toluene shape selective alkylation.
2. The process according to claim 1 , characterized in that the organic amine therein is at least one selected from the group consisting of diethylamine, propylamine, triethylamine, ethylamine, dipropylamine and tripropylammonium bromide; the alcohol therein is selected from the group consisting of primary alcohol, secondary alcohol and mixtures thereof; the ether is selected from the group consisting of alkyl ether and mixtures thereof.
3. The process according to claim 2 , characterized in that the organic amine is selected from the group consisting of ethylamine, triethylamine and mixtures thereof; the primary alcohol is selected from the group consisting of methanol and ethanol; the secondary alcohol is isopropanol; and the ether therein is selected from the group consisting of diethyl ether and dimethyl ether.
4. The process according to claim 1 , characterized in that the organic amine/alcohol is in a weight ratio of 0.05-10:1.
5. The process according to claim 4 , characterized in that the organic amine/alcohol is in a weight ratio of 0.1-1:1.
6. The process according to claim 1 , characterized in that the organic amine/ether is in a weight ratio of 0.05-15:1.
7. The process according to claim 1 , characterized in that the organic amine/ether is in a weight ratio of 0.1-5:1.