Ammonia → HCID 131718397, compound

HRID 1464536Notes

Reaction equation

[CH3:1][O:2][Si](OC)(OC)OC.[Si:10]([O:23][O:24][CH2:25][CH3:26])([O:19][O:20][CH2:21][CH3:22])([O:15][O:16][CH2:17][CH3:18])[O:11][O:12][CH2:13][CH3:14].[Si](OCC)(OCC)(OCC)OCC.Cl.[NH4+].[OH-].N>O.CO.C(O)C>[Si:10]([O:15][O:16][CH2:17][CH3:18])([O:19][O:20][CH2:21][CH3:22])([O:23][O:24][CH2:25][CH3:26])[O:11][O:12][CH2:13][CH3:14].[CH3:1][OH:2]

Participants

Conditions

Temperature: 60 °C

Procedure

These examples are the same as Example 1, except that the formulations for silica aerogel were different. Since TMOS is not available in commercial quantities and is more expensive, a cheaper alternative was sought. For Example 7A this new composition involved tetraethoxy orthosilicate (TEOS) and methanol. Methanol was selected as a preferred alcohol based on the lower cost for commercial quantities. However, other alcohols such as ethanol can also be used. The procedure for preparing this gel can be described by these two reactions: ##STR1## The molar ratio of Si(OC2H5)4 :H 2O:HCl:NH4OH:CH3OH is equal to 1:3:0.0007:0.00124:3.75. In the first step only 1 mole of water/mole silicon was added along with methanol and HCl acid. This mixture was stirred and heated at 60° C. for 1 hour. In the second step a mixture of left over water and ammonia base was added at 0°-5° C. to slow down the condensation reaction. This gel was slightly cloudy as compared to TMOS gels. The bulk densities of the AMCs produced from TEOS/CH3OH were found to be more dense (i.e. 1.1-1.8 times) than those of TMOS AMCs.

Workup

customThe procedure for preparing this gel
additionIn the second step a mixture
additionwas added at 0°-5° C.
customthe condensation reaction

Sources & evidence

ORD record: ord-31cd4fd83b0b48c180592fbe95e60f69
Source dataset: uspto-grants-1994_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05306555

Reaction notes

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