tert-Butylation of naphthalene by tertiary butanol over HY zeolite and cerium-modified HY catalysts

2017 ◽  
Vol 7 (20) ◽  
pp. 4700-4709 ◽  
Author(s):  
Zhihua Huang ◽  
Jie Zhang ◽  
Peidong Li ◽  
Lanjian Xu ◽  
Xiaomin Zhang ◽  
...  
Keyword(s):  
Acid Strength ◽  
Hy Zeolite ◽  
Tertiary Butanol

Cerium-modified HY catalysts exhibit a high 2,6-/2,7-DTBN ratio in naphthalene tert-butylation due to the weakened acid strength.

Acid Strength Measurement of Zeolites by the TPD-IR Technique with Ammonia as Probe Molecule

2013 ◽  
Vol 475-476 ◽  
pp. 1270-1274
Author(s):  
Bin Wang ◽  
Ying Zhang ◽  
Fu Bo Gu ◽  
Min Zuo ◽  
Guang Sheng Guo
Keyword(s):  
Acid Sites ◽  
Acid Strength ◽  
Probe Molecule ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Hy Zeolite ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

An improved TPD-IR technique was developed recently. By which means, acid properties of Brønsted acid sites on HY zeolite and SAPO-34 zeolite were studied by an advanced TPD-IR technique with ammonia as probe molecule. Desorption activation energy (DAE) of the probe molecule adsorbed on zeolite was used as a measure of the acid strength. The result indicates the Brønsted acid sites of HY Zeolite or SAPO-34 zeolite were divided into two types with the strength of DAE of ammonia 43.4KJ/mol, 24.4KJ/mol and 33.2KJ/mol, 20.5KJ/mol. It is concluded that HY zeolite has the stronger Brønsted acid sites than that of SAPO-34 zeolite.

Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

2017 ◽  
Vol 68 (1) ◽  
pp. 116-120
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
Lucian Mihail Birsa ◽  
Ioan Gabriel Sandu ◽  
Laura Gabriela Sarbu ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Metal Content ◽  
Pulse Method ◽  
Acid Strength ◽  
Strength Distribution ◽  
Zeolite Catalysts ◽  
Benzene Toluene ◽  
Acid Strength Distribution ◽  
Silver Cations ◽  
Heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

Aromatization of C2-C6 Aliphatic Hydrocarbons on Copper-Containing ZSM-5 Zeolites

1992 ◽  
Vol 57 (12) ◽  
pp. 2553-2560
Author(s):  
Zdravka Popova ◽  
Katia Aristirova ◽  
Christo Dimitrov
Keyword(s):  
Copper Content ◽  
Acid Strength ◽  
The State ◽  
Aliphatic Hydrocarbons ◽  
Bronsted Acid ◽  
Ion Formation ◽  
Brönsted Acid ◽  
Wide Range ◽  
Carbenium Ion ◽  
Acid Centers

The aromatization of a wide range of model aliphatic and cycloaliphatic hydrocarbons (ethene, ethane, propene, n-hexane, 1-hexene, methylcyclopentane, cyclohexane, cyclohexene) on copper-containing NaZSM-5 and HZSM-5 zeolites has been investigated. It was established that the degree of aromatization is related to carbenium ion formation and depends on the acid strength and copper content of zeolite. Experiments with copper-containing samples reduced prior to use indicated the possibility to enhance the selectivity to aromatization. The change of the state of Cu2+ ions during catalytic experiments confirmed the assumption about participation of Cu0 simultaneously with the Bronsted acid centers in the dehydrogenation/hydrogenation steps.

Preparation of Strong Acid Catalysts by Sulfate Treatment of Calcined Boehmite

1992 ◽  
Vol 57 (11) ◽  
pp. 2241-2247 ◽  
Author(s):  
Tomáš Hochmann ◽  
Karel Setínek
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Aluminum Sulfate ◽  
Solid Acid ◽  
Strong Acid ◽  
Acid Strength ◽  
Solid Acid Catalysts ◽  
Acid Catalysts ◽  
Preparation Methods ◽  
Indicator Method

Solid acid catalysts with acid strength of -14.52 < H0 < -8.2 were prepared by sulfate treatment of the samples of boehmite calcined at 105-800 °C. Two preparation methods were used: impregnation of the calcined boehmite with 3.5 M H2SO4 or mixing of the boehmite samples with anhydrous aluminum sulfate, in both cases followed by calcination in nitrogen at 650 °C. The catalysts were characterized by measurements of surface area, adsorption of pyridine and benzene, acid strength measurements by the indicator method and by catalytic activity tests in the isomerization of cyclohexene, p-xylene and n-hexane. Properties of the catalysts prepared by both methods were comparable.

scholarly journals Plastic waste to fuels by hydrocracking at mild conditions

2021 ◽  
Vol 7 (17) ◽  
pp. eabf8283
Author(s):  
Sibao Liu ◽  
Pavel A. Kots ◽  
Brandon C. Vance ◽  
Andrew Danielson ◽  
Dionisios G. Vlachos
Keyword(s):  
Direct Method ◽  
Acid Sites ◽  
Liquid Fuels ◽  
High Yield ◽  
Tandem Catalysis ◽  
Hy Zeolite ◽  
Environmental Threat ◽  
Single Use ◽  
Initial Activation ◽  
A Direct Method

Single-use plastics impose an enormous environmental threat, but their recycling, especially of polyolefins, has been proven challenging. We report a direct method to selectively convert polyolefins to branched, liquid fuels including diesel, jet, and gasoline-range hydrocarbons, with high yield up to 85% over Pt/WO3/ZrO2 and HY zeolite in hydrogen at temperatures as low as 225°C. The process proceeds via tandem catalysis with initial activation of the polymer primarily over Pt, with subsequent cracking over the acid sites of WO3/ZrO2 and HY zeolite, isomerization over WO3/ZrO2 sites, and hydrogenation of olefin intermediates over Pt. The process can be tuned to convert different common plastic wastes, including low- and high-density polyethylene, polypropylene, polystyrene, everyday polyethylene bottles and bags, and composite plastics to desirable fuels and light lubricants.

scholarly journals Decrease in Acid Strength of Propionate Side-chains of Hæmatin on Reduction to Hæm

Nature ◽  
1959 ◽  
Vol 184 (4701) ◽  
pp. 1808-1808 ◽  
Author(s):  
J. E. O'HAGAN
Keyword(s):  
Acid Strength ◽  
Side Chains
Sign in / Sign up

Export Citation Format

Share Document