Microporous and mesoporous carbon xerogel having a characteristic mesopore size and precursors thereof and a process for producing these and their use

A technology of dry gel and wet gel, which is applied in the field of preparation of sol-gel method, and can solve the problem of not finding the characteristic repeating parameters of carbon aerogel and xerogel

Inactive Publication Date: 2011-06-01
EVONIK CARBON BLACK GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] For carbon aerogels, generally, the pore size distribution varies over a relatively wide range as a function of analytical parameters and production process; until now, no pore size distribution common to carbon aerogels and xerogels and independent of analytical parameters has been found. characteristic repeat parameter

Method used

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  • Microporous and mesoporous carbon xerogel having a characteristic mesopore size and precursors thereof and a process for producing these and their use
  • Microporous and mesoporous carbon xerogel having a characteristic mesopore size and precursors thereof and a process for producing these and their use
  • Microporous and mesoporous carbon xerogel having a characteristic mesopore size and precursors thereof and a process for producing these and their use

Examples

Experimental program
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Effect test

Embodiment 1

[0016] In a beaker, mix 3.66g phenol with 6.24g formaldehyde solution (37% aqueous formaldehyde solution stabilized with about 10% methanol) and 26.27g n-propanol (corresponding to the molar ratio F / P=2 of formaldehyde and phenol, phenol and The mass concentration of the formaldehyde reactant in the total solution (M=15%) is mixed. The solution was stirred on a magnetic stirrer until the phenol was completely dissolved. Subsequently, 3.83 g of 37% HCl were added (corresponding to a molar ratio of phenol to catalyst P / C=1). The solution was then added to a beaded edge bottle with a height of 10 cm (3 cm in diameter), and the beaded edge bottle was sealed airtight. The crimp bottle and samples were heated together in an oven at 85°C for 26h.

[0017] After 26 h, the monolithic organic wet gel was obtained, which was then convection dried in a drying oven at 65° C. for 70 h. Gained overall organic PF xerogel has 0.37g / cm 3 The macroscopic density (macroscopic density). Organ...

Embodiment 2

[0019] In a beaker, 6.11 g of phenol were mixed with 10.39 g of formaldehyde solution (37% aqueous formaldehyde solution stabilized with about 10% methanol) and 21.38 g of n-propanol (corresponding to F / P=2; M=25%). The solution was stirred on a magnetic stirrer until the phenol was completely dissolved. Subsequently, 2.18 g of 37% HCl (corresponding to P / C=2.95) were added. Then the solution was added into a crimp bottle with a height of 10 cm (3 cm in diameter), and the crimp bottle was sealed airtight. The crimp bottle and samples were heated together in an oven at 85°C for 24h.

[0020] After 24 h, the monolithic organic wet gel was obtained, which was then convection dried in a drying oven at 65° C. for 72 h. This gives a monolithic, ocher organic PF xerogel with 0.48 g / cm 3 macro density. From Figure 4 The specific surface area (BET surface area) calculated by the adsorption isotherm is 157m 2 / g, the external area is 130m 2 / g, mesopore volume is 0.38cm 3 / g. ...

Embodiment 3

[0022] In a beaker, 6.11 g of phenol were mixed with 3.89 g of paraformaldehyde and 27.87 g of n-propanol (corresponding to F / P=2; M=25). Stir the solution on a magnetic stirrer until the phenol and paraformaldehyde are completely dissolved. Subsequently, 2.14 g of 37% HCl (corresponding to P / C=3) were added. Then the solution was added into a crimp bottle with a height of 10 cm (3 cm in diameter), and the crimp bottle was sealed airtight. The crimp bottle and samples were heated together in an oven at 85°C for 24h.

[0023] After 24 h, the monolithic organic wet gel was obtained, which was then convection dried in a drying oven at 65° C. for 96 h. This obtains a 3 Macroscopic densities of monolithic organic PF xerogels. Organic PF xerogels were transformed into carbon xerogels by pyrolysis at 800 °C under argon atmosphere. The resulting carbon xerogel has a 1.14g / cm 3 The macro density, the specific surface area (BET) is 256m 2 / g, the micropore volume is 0.10cm 3 / g, ...

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Abstract

The invention relates to a microporous and mesoporous carbon xerogel and organic precursors thereof based on a phenol-formaldehyde xerogel. A characteristic parameter common to carbon xerogels is a peak in the mesopore size distribution determined by the BJH method (Barrett-Joyner-Halenda) from nitrogen absorption measurements at 77 K in the range from 3.5 nm to 4 nm. The production process is characterized firstly by the low starting material costs (use of phenol instead of resorcinol) and secondly by very simple and cost-effective processing; convective drying without solvent exchange instead of supercritical drying or freeze drying. The carbon xerogels and their organic phenol-formaldehyde xerogel precursors have densities of 0.20-1.20 g / cm3, corresponding to a porosity of up to 89%, and the xerogels can also have a relevant mesopore volume. The carbon xerogels obtained from the phenol-formaldehyde xerogels are also microporous.

Description

technical field [0001] The present invention provides a porous carbon xerogel with a characteristic mesopore size and its precursor in the form of a phenol-formaldehyde xerogel (PF xerogel), and by subcritical Preparation method of sol-gel method of drying wet gel. These phenol-formaldehyde based carbon xerogels (= pyrolyzed PF gels) are typically characterized by a pore size distribution between 3.5 nm and 4.0 nm measured by nitrogen adsorption at 77 K using the BJH method (Barrett-Joyner-Halenda; DIN 66134). with clearly identifiable peaks. Background technique [0002] Aerogels, cryogels and xerogels find application in many fields. In principle, said materials differ according to the type of drying method. Aerogels are defined by supercritical drying, cryogels by freeze drying, and xerogels by convective subcritical drying under standard conditions. [0003] Aerogels are materials with very good adaptability of their morphological properties; their fields of use are ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J13/00C08J9/28C01B31/08C04B38/00
CPCC08J2361/00C08J2201/0504B01J13/0091C04B38/0045C08J2205/02C04B38/0022C04B2111/94C08J9/28C01B31/00C04B2111/00793C01B32/00Y02E60/50C04B35/52C04B38/0054C01B32/30B01J13/00B01J20/20H01M4/96
Inventor C·舍德尔G·赖歇瑙尔
Owner EVONIK CARBON BLACK GMBH
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