US20080058565A1 - Boron carbide as an effective friedel-crafts type catalyst - Google Patents
Boron carbide as an effective friedel-crafts type catalyst Download PDFInfo
- Publication number
- US20080058565A1 US20080058565A1 US11/897,508 US89750807A US2008058565A1 US 20080058565 A1 US20080058565 A1 US 20080058565A1 US 89750807 A US89750807 A US 89750807A US 2008058565 A1 US2008058565 A1 US 2008058565A1
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- US
- United States
- Prior art keywords
- boron carbide
- type catalyst
- friedel
- catalysts
- crafts type
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/14—Preparation of carboxylic acid esters from carboxylic acid halides
Abstract
The compound, boron carbide, B4C, is an effective catalyst for the conversion of benzylic halides to polybenzyls.
Description
- This application is a divisional of application Ser. No. 11/442,716 examined by J. Parsa.
- Friedel-Craft alkylation and acylation reactions of organic compounds have been commonly performed with Lewis acid catalysts. However, the use of Lewis acid catalysts in commercial practice has presented problems of the catalysts being corrosive, difficult to recover and the generation of hazardous waste.
- Examples of such reactions are described in the text by P. Bruice, Organic Chemistry, 4th edition, Prentice Hall, 2004, pg. 612 and following. A common catalyst employed in both alkylation and acylation reactions is the Lewis acid AlCl3. Although AlCl3 is referred to as a catalyst in the true sense, it is not. It requires stoichiometric amounts of AlCl3 since it actually forms a complex with the reactant that subsequently requires its removal from the reaction mixture by either an acid or base hydrolysis. Such a procedure is costly and, in the process, toxic waste is generated which must be disposed of. Other Lewis acid catalysts have been investigated which include zeolites as disclosed in U.S. Pat. Nos. 4,547,605 and 4,717,780. Although the zeolites are effective Lewis acid catalysts there use is often limited by the pore size of the zeolite which inhibit large sterically hindered molecules from reaching the active site within the zeolite.
- Numerous Lewis acid catalysts have been disclosed which include both transition and non-transition metals as disclosed in U.S. Pat. No. 4,414,406 and U.S. Pat. No. 6,184,418, however often the catalysts are difficult to prepare or exhibit chemical reactivity that limits their use. Numerous disclosures include the utilization of mixed catalysts as described in U.S. Pat. No. 5,750,455.
- Although much effort has been made to develop more effective catalysts for both alkylation and acylation of organic compounds, there is a need for more effective catalysts that do not have the inherent problems of the ones currently employed. An ideal catalyst would be one that functions as a heterogenous catalyst, easily removed from the reactants and products, chemically and thermally stable, and readily available or easily prepared, and inexpensive.
- I have discovered that boron carbide, B4C is an effective catalyst for Friedel-Crafts type reactions. It is readily available, chemically and thermally stable, requires no pretreatment, and is easily recoverable from the reaction products.
- Since B4C functions as a heterogenous catalyst and is non-toxic, no hazardous waste is generated at the conclusion of the reaction. The use of B4C requires no time consuming work up at the end of the reaction and can be reused without any regeneration or activation procedures. This discovery is unexpected since B4C is regarded in the literature as compound that is essentially unreactive.
- The current literature teaches that catalysts for Friedel-Crafts reactions are classified as Lewis acid catalysts. Although many materials have been investigated as Friedel-Craft catalysts they are all recognized as Lewis acid type catalysts. These include zeolites, clays, heteropoly acids, and various metal halides.
- I have discovered that the non-metal carbide, boron carbide, B4C can function as a catalyst in alkylation of aromatic compounds, previously conducted by Lewis acid Friedel-Craft type catalysts. This is unexpected since boron carbide is regarded as a compound that has a high resistance to chemical attack.
- Boron carbide in an extremely hard material whose melting point is 2450° C. It is commonly used as an abrasive in lapping applications and as a refractory. It is also known to be a neutron absorber and is use in the nuclear industry. There are no reports in the chemical literature that boron carbide exhibits any chemical or physical properties that would indicate that it would function as a catalyst. This unexpected discovery is surprising in regard to the teachings in the prior art.
- I have discovered that boron carbide is suitable for the alkylation of aromatics to produce polybenzyls. The rate of the reaction depends on both the amount of boron carbide present, its particle size and the temperature at which the reaction is conducted. The reactions are carried out by contacting the corresponding benzyl halide in the presence of the boron carbide. These reactions proceed to completion at temperatures ranging from 80° to 160° C.
- This reaction can easily be observed by heating 20 ml of benzyl chloride to about 120° C. in an evaporating dish. At the end of an hour no observable reaction has taken place. If, at this point, 0.10 gm of boron carbide is added to the benzyl chloride within minutes copious amounts of HCl is evolved and the benzyl chloride is transformed into a dark viscous mass, which is the polybenzyl product.
- The following examples illustrate the embodiments of this invention, however, it is understood, that they are presented only for illustrative purposes and do not limit the scope of this invention.
- A mixture of 12.6 gm (mole) benzyl chloride and 0.1 gm of boron carbide was heated in an evaporating dish, with continuous stirring to 120° C. Initially copious amounts of HCl gas evolved, ceasing in about two hours. The viscous mixture solidified on cooling. The solid material was dissolved in benzene and the catalyst was removed by filtration. The benzene was then removed at reduced pressure and the remaining viscous material was identified as polybenzyl from its infrared and NMR spectra.
- A mixture of 7.4 gm (0.04 moles) of benzyl bromide and 0.2 gm of boron carbide in 175 ml of benzene was refluxed for 24 hours. The solution was allowed to cool and filtered to remove the boron carbide. The benzene was removed at reduced pressure and 5.4 gm of a solid product was recovered. It was identified as diphenylmethane by its infrared and NMR spectra.
Claims (3)
1. A process for the alkylation of benzylic halides to produce polybenzyls by contacting the benzylic halides in the presence of the catalyst boron carbide at a temperature of 100° C. to 180° C.
2. The process in claim 1 in which the reacting benzylic halide is benzyl chloride.
3. The process in claim 1 in which the benzylic halide is an alkyl substituted benzyl chloride.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/897,508 US20080058565A1 (en) | 2006-05-30 | 2007-08-31 | Boron carbide as an effective friedel-crafts type catalyst |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/442,716 US7279604B2 (en) | 2005-05-31 | 2006-05-30 | Boron carbide as an effective Friedel-Crafts type catalyst |
US11/897,508 US20080058565A1 (en) | 2006-05-30 | 2007-08-31 | Boron carbide as an effective friedel-crafts type catalyst |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/442,716 Division US7279604B2 (en) | 2005-05-31 | 2006-05-30 | Boron carbide as an effective Friedel-Crafts type catalyst |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080058565A1 true US20080058565A1 (en) | 2008-03-06 |
Family
ID=39152689
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/897,507 Expired - Fee Related US7393970B2 (en) | 2006-05-30 | 2007-08-31 | Boron carbide as an effective friedel-crafts type catalyst |
US11/897,508 Abandoned US20080058565A1 (en) | 2006-05-30 | 2007-08-31 | Boron carbide as an effective friedel-crafts type catalyst |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/897,507 Expired - Fee Related US7393970B2 (en) | 2006-05-30 | 2007-08-31 | Boron carbide as an effective friedel-crafts type catalyst |
Country Status (1)
Country | Link |
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US (2) | US7393970B2 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4414406A (en) * | 1980-09-29 | 1983-11-08 | Standard Oil Company (Indiana) | Class of Friedel-crafts catalysts |
US4547605A (en) * | 1983-09-28 | 1985-10-15 | Mobil Oil Corporation | Catalyst for alkylation of aromatic hydrocarbons |
US4717780A (en) * | 1985-06-27 | 1988-01-05 | Mobil Oil Corp. | Catalytic aromatics conversion |
US5750455A (en) * | 1994-10-24 | 1998-05-12 | Institut Francais Du Petrole | Catalytic composition and process for the alkylation of aliphatic hydrocarbons |
US6184418B1 (en) * | 1995-09-25 | 2001-02-06 | Rhodia Chimie | Aromatic compound acylation method |
-
2007
- 2007-08-31 US US11/897,507 patent/US7393970B2/en not_active Expired - Fee Related
- 2007-08-31 US US11/897,508 patent/US20080058565A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4414406A (en) * | 1980-09-29 | 1983-11-08 | Standard Oil Company (Indiana) | Class of Friedel-crafts catalysts |
US4547605A (en) * | 1983-09-28 | 1985-10-15 | Mobil Oil Corporation | Catalyst for alkylation of aromatic hydrocarbons |
US4717780A (en) * | 1985-06-27 | 1988-01-05 | Mobil Oil Corp. | Catalytic aromatics conversion |
US5750455A (en) * | 1994-10-24 | 1998-05-12 | Institut Francais Du Petrole | Catalytic composition and process for the alkylation of aliphatic hydrocarbons |
US6184418B1 (en) * | 1995-09-25 | 2001-02-06 | Rhodia Chimie | Aromatic compound acylation method |
Also Published As
Publication number | Publication date |
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US20080058545A1 (en) | 2008-03-06 |
US7393970B2 (en) | 2008-07-01 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |