Vacuum in Situ Characterized System

Main Property

Vacuum in situ characterized system is designed as special vacuum system for infrared spectrum adsorption characterization and catalyst acid determination, equipped with quartz infrared adsorbed pool, can be connected for use with spectrometers like Bruker, Nicolet, PE, Shimadzu, Jasco and Varian/Bio-Rad.

 

 

Applications

Adsorbed State Research and Catalyst Characterization

Infrared Spectrum has been widely used in the research of catalyst surface property, and one of the most effective and popular application is the research of the so-called “probe molecule” adsorbed on the surface of catalyst, such as NO, CO, CO2 , NH3, and C3 H5 N. It can provide the “active center” information existed on the surface of catalyst. This method can characterize the atoms and ions exposed on the catalyst surface and reveal the surface structure more deeply. Compared with other methods, the information obtained from such infrared research is limited to the catalyst work surface which the probe molecule (or reactant molecule) can be close to or barrier allowed to.

Adsorbed State Research for CO

As CO has electric authorized property, empty orbit unfilled easily interacts with transition metal. CO has close relations with many important catalytic reactions, such as carbonyl synthesis, water gas synthesis and oxidation, and it has high infrared extinction coefficient. Therefore, the research of adsorbed state on the surface of transition metal is very wide subject.

The catalyst research on double atomic metal cluster (Infrared spectrum method studies the surface composition and interaction of catalyst)

Using two kinds of gas mixture adsorbed in catalyst of two-component transition metal, through infrared spectrum to measure its adsorption band intensity adsorbed in different component, this method can determine the surface composition of double metal carrier. For example, the infrared spectrum by CO and NO mixture adsorbed in Pt-Ru/SiO2 can determine the surface composition of its catalyst.

Infrared Acid Determination for Catalyst

The acid center is generally regarded as reactive center for catalyst surface of oxidation. In catalytic cracking, isomerization and polymerization, hydrocarbon molecules and surface acid center interact to form carbonium ion, which is the intermediate compound of reaction. The theory of carbonium ion can not only successfully explain the reaction of hydrocarbon on oxidation surface, but also provide powerful proof for the existence of acid center. In order to further characterize the acid catalyst of solid, the types (L acid, B acid), intensity and acid quantity in the surface acid center need to be determined. The alkaline adsorption mass, such as ammonia, pyridine, trimethyl amine and n-butyl amine, are generally used to do the research of surface acid by infrared spectrum, among which the pyridine and ammonia used to research solid acid by infrared spectrum are most widely employed.

Research of Hydroxyl on Oxidation Surface

Infrared used in reaction dynamics research

The solving problems of high vacuum system of Catalyst in situ Characterization

Technical Parameter

1. The vacuum degree in the sample pool should reach 10-5Torr within 30 minutes after sample processing starts.

2. In the process of sample measurement, each sample can simultaneously or separately adsorbs or desorbs probe molecule.

3. As the probe molecule needed in the measurement is acid or alkaline, high borosilicate glass avoids the pollution of each other.

4. The vacuum processing system is combined with mechanical pump and glass level 4 diffusion pump in series to do air exhaust, to meet the customer requirement of high vacuum in testing pool, fast pumping speed, small noise, simple operation, easy to use and moderate price.

5. The low vacuum part mainly is the high concentration gas in exhausting system or residual gas adsorbed.

6. Each part of the section selects high borosilicate glass, meet the system requirement of high vacuum, transparent to operate and convenient to adjust.

7. The vacuum measurement instrument uses vacuum gauge with digital display and high precision.

8. This system is equipped with transmissive quartz and infrared spectrum adsorption pool, using the transmission mode, the sample with a series of process, like calcination, flow redox, exhausting degassing and adsorption reaction, being immigrated or removed to the light way of infrared spectrometer to do the experiment, and also can use the equipped extension pipeline for in situ characterization and experiment. Its heating mode can use temperature programmed method to control the rise and fall of temperature, also can use regulating transformer to control the temperature. The using temperature can be as high as 45℃. Adsorption pool window with standard configuration is CaF2, 4000-1200 wave number for working area. The user can also configure the other windows for other material according to their own requirements.

9. In the process of sample measurement, each sample can simultaneously or separately pretreats, adsorbs and desorbs probe molecule or changes sample.

10. It is convenient to change bellows.

11. The vacuum system can change correspondingly to meet customer requirements.

 

Configuration Sheet

S/C		Equipment Description	Quantity
High Vacuum Device	1.1	Mechanical Pump	1
	1.2	Glass Oil Diffusion Pump	1
	1.3	Vacuum Gauge	1
	1.4	Header of Pressure Gage	1
	1.5	Adsorption Trap, Cooling Chamber, Pipeline, Vacuum Hanging-up, Glass Section, Standard Connector with Electric Control	1
Measurement System	2.1	Sample Pool	1
	2.2	Temperature Control Device	1
	2.3	Operation Manual	1