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115-11-7 Usage

Physical properties

Colorless gas with a coal gas-like odor. The odor threshold concentration is 10 ppmv Nagata and Takeuchi (1990). This gas can be liquefied under pressure. The substance has low solubility in water, soluble in organic solvent, easy to polymerize. It is nonexplosive; however, it forms explosive mixtures with air. Containers holding isobutylene under pressure may explode if heated. The boiling point and freezing point of isobutylene are -6.9°C (19.6°F) and -141°C (-221°F), respectively. Isobutylene is extremely flammable. It is stable under recommended storage conditions and no decomposition may occur if stored and applied as directed.

Uses

Different sources of media describe the Uses of 115-11-7 differently. You can refer to the following data:
1. Isobutylene is used as a monomer for the production of various polymers such as butyl rubber, polybutene and polyisobutylene. The most important application of butyl rubber is the manufacture of tyres for cars and other vehicles. Other applications of butyl rubber, polybutene and poyisobutylene are lubricants (motor oils), adhesives, sealants and coatings. Another major use of isobutylene is the production of methyl-tert-butyl ether (MTBE) and ethy-tert-butyl ether (ETBE) which are gasoline blending components for cleaner burning fuels. Isobutylene is also used for the production of anti-oxidants, fragrances and gas odorization products.
2. Primarily used to produce diisobutylene, trimers, butyl rubber, and other polymers; also to produce antioxidants for foods, packaging, food supplements, and for plastics: Hatch, Pet. Refin. 39, No. 6, 207 (1960).

Definition

ChEBI: isobutylene is an alkene that is prop-1-ene substituted by a methyl group at position 2. It is an alkene and a gas molecular entity.

Application

Isobutylene is an important petrochemical raw material. In the pesticide industry, it is mainly used for the preparation of the organophosphorus insecticide terbufos, the pyrethroid insecticide permethrin and the acaricide pyridaben. Industrially, high-concentration isobutylene is mainly used for the production of polyisobutylene and copolymerization with isoprene to produce butyl rubber. The alkylation reaction of isobutene and isobutane can produce high-octane alkylated gasoline, and methyl tert-butyl ether obtained by reacting with methanol is an excellent gasoline additive.

Production Methods

Isobutene is produced in refinery streams by absorption on 65% H2SO4 at about 15C, or by reacting with an aliphatic primary alcohol and then hydrolyzing the resulting ether.

General Description

Isobutylene is a colorless gas with a faint petroleum-like odor. For transportation it may be stenched. It is shipped as a liquefied gas under its own vapor pressure. Contact with the liquid can cause frostbite. It is easily ignited. Its vapors are heavier than air and a flame can flash back to the source of leak very easily. The leak can either be a liquid or vapor leak. It can asphyxiate by the displacement of air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. It is used in the production of isooctane, a high octane aviation gasoline.

Air & Water Reactions

Highly flammable.

Reactivity Profile

ISOBUTYLENE is incompatible with oxidizers. ISOBUTYLENE polymerizes easily. ISOBUTYLENE reacts easily with numerous materials, such as alkyl halides, halogens, concentrated sulfuric acid, hypochlorous acid, aluminum chloride, carbon monoxide and hydrogen with a cobalt catalyst. Polymerization is catalyzed by aluminum chloride and boron trifluoride.

Hazard

Highly flammable, dangerous fire and explosion risk, explosive limits in air 1.8–8.8%.

Health Hazard

Inhalation of moderate concentrations causes dizziness, drowsiness, and unconsciousness. Contact with eyes or skin may cause irritation; the liquid may cause frostbite.

Fire Hazard

Behavior in Fire: Containers may explode in fire. Vapor is heavier than air and may travel a long distance to a source of ignition and flash back.

Flammability and Explosibility

Extremelyflammable

Carcinogenicity

Groups of 50 male and 50 female F344/N rats were exposed to isobutene at concentrations of 0, 500, 2000, or 8000 ppm6 h/day 5 days/week for 105 weeks. Groups of 50 male and 50 female B6C3F1 mice were exposed to isobutene at concentrations of 0, 500, 2000, or 8000 ppm 6 h/day, 5 days/week for 105 weeks. Under the conditions of these 2 year inhalation studies, there was some evidence of the carcinogenic activity of isobutene in male F344/N rats based on an increased incidence of follicular cell carcinoma of the thyroid gland. There was no evidence of the carcinogenic activity of isobutene in female F344/N rats or male or female B6C3F1 mice exposed to 500, 2000, or 8000 ppm.

Source

Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rate of 2-methylpropene was 40.1 mg/kg of pine burned. Emission rates of 2-methylbutene were not measured during the combustion of oak and eucalyptus. California Phase II reformulated gasoline contained 2-methylpropene at a concentration of 170 mg/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 15.6 and 427 mg/km, respectively (Schauer et al., 2002).

Environmental fate

Photolytic. Products identified from the photoirradiation of 2-methylpropene with nitrogen dioxide in air are 2-butanone, 2-methylpropanal, acetone, carbon monoxide, carbon dioxide, methanol, methyl nitrate, and nitric acid (Takeuchi et al., 1983). Similarly, products identified from the reaction of 2-methylpropene with ozone included acetone, formaldehyde, methanol, carbon monoxide, carbon dioxide, and methane (Tuazon et al., 1997). The following rate constants were reported for the reaction of 2-methylpropene and OH radicals in the atmosphere: 3.0 x 10-13 cm3/molecule?sec at 300 K (Hendry and Kenley, 1979); 5.40 x 10-11 cm3/molecule?sec (Atkinson et al., 1979); 5.14 x 10-11 at 298 K (Atkinson, 1990). Reported reaction rate constants for 2-methylpropene and ozone in the atmosphere include 2.3 x 10-19 cm3/molecule?sec (Bufalini and Altshuller, 1965); 1.17 x 10-19 cm3/molecule?sec at 300 K (Adeniji et al., 1965); 1.21 x 10-17 cm3/molecule?sec at 298 K (Atkinson, 1990). Chemical/Physical. Complete combustion in air yields carbon dioxide and water. Incomplete combustion yields carbon monoxide.

Solubility in organics

(mole fraction):In 1-butanol: 0.131, 0.0695, and 0.0458 at 25, 30, and 70 °C, respectively; chlorobenzene: 0.234, 0.132, and 0.0796 at 25, 30, and 70 °C, respectively; octane: 0.333, 0.184, and 0.119 at 25, 30, and 70 °C, respectively (Hayduk et al., 1988).

Purification Methods

Dry isobutene by passage through anhydrous CaSO4 at 0o. Purify it further by freeze-pump-thaw cycles and trap-to-trap distillation. [Beilstein 1 IV 796.]

Check Digit Verification of cas no

The CAS Registry Mumber 115-11-7 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,1 and 5 respectively; the second part has 2 digits, 1 and 1 respectively.
Calculate Digit Verification of CAS Registry Number 115-11:
(5*1)+(4*1)+(3*5)+(2*1)+(1*1)=27
27 % 10 = 7
So 115-11-7 is a valid CAS Registry Number.
InChI:InChI=1/C4H8/c1-4(2)3/h1H2,2-3H3

115-11-7 Well-known Company Product Price

  • Brand
  • (Code)Product description
  • CAS number
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  • Detail
  • TCI America

  • (I0909)  Isobutene (ca. 8% in Dichloromethane)  

  • 115-11-7

  • 100mL

  • 400.00CNY

  • Detail
  • TCI America

  • (I0909)  Isobutene (ca. 8% in Dichloromethane)  

  • 115-11-7

  • 500mL

  • 1,280.00CNY

  • Detail
  • TCI America

  • (I0910)  Isobutene (ca. 10% in Isopropyl Ether)  

  • 115-11-7

  • 100mL

  • 310.00CNY

  • Detail
  • TCI America

  • (I0910)  Isobutene (ca. 10% in Isopropyl Ether)  

  • 115-11-7

  • 500mL

  • 980.00CNY

  • Detail
  • TCI America

  • (I0911)  Isobutene (ca. 15% in Tetrahydrofuran)  

  • 115-11-7

  • 100mL

  • 310.00CNY

  • Detail
  • TCI America

  • (I0911)  Isobutene (ca. 15% in Tetrahydrofuran)  

  • 115-11-7

  • 500mL

  • 980.00CNY

  • Detail
  • Aldrich

  • (295469)  2-Methylpropene  99%

  • 115-11-7

  • 295469-450G-EU

  • 9,477.00CNY

  • Detail

115-11-7SDS

SAFETY DATA SHEETS

According to Globally Harmonized System of Classification and Labelling of Chemicals (GHS) - Sixth revised edition

Version: 1.0

Creation Date: Aug 10, 2017

Revision Date: Aug 10, 2017

1.Identification

1.1 GHS Product identifier

Product name Isobutene

1.2 Other means of identification

Product number -
Other names Propene,2-methyl

1.3 Recommended use of the chemical and restrictions on use

Identified uses For industry use only. Adhesives and sealant chemicals,Fuels and fuel additives,Intermediates,Lubricants and lubricant additives,Solvents (which become part of product formulation or mixture)
Uses advised against no data available

1.4 Supplier's details

1.5 Emergency phone number

Emergency phone number -
Service hours Monday to Friday, 9am-5pm (Standard time zone: UTC/GMT +8 hours).

More Details:115-11-7 SDS

115-11-7Synthetic route

tert-butyl alcohol
75-65-0

tert-butyl alcohol

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With air oxidized carbon nanotubes at 120℃; Kinetics; Reagent/catalyst; Temperature; Flow reactor; Inert atmosphere; chemoselective reaction;100%
With aminosulfonic acid In acetic anhydride at 80℃; for 0.5h; Dehydration;98%
niobium silicate at 250℃;98.9%
cyclohexane
110-82-7

cyclohexane

1,1,3,3-tetramethyl-2,3-dihydro-1H-isoindol-2-yloxoyl radical
80037-90-7

1,1,3,3-tetramethyl-2,3-dihydro-1H-isoindol-2-yloxoyl radical

2-(t-butylazo)prop-2-yl hydroperoxide
37421-16-2

2-(t-butylazo)prop-2-yl hydroperoxide

A

2-cyclohexyloxy-1,1,3,3-tetramethyl-2,3-dihydro-1H-isoindole
89482-40-6

2-cyclohexyloxy-1,1,3,3-tetramethyl-2,3-dihydro-1H-isoindole

B

2-tert-butoxy-1,1,3,3-tetramethylisoindoline
93524-81-3

2-tert-butoxy-1,1,3,3-tetramethylisoindoline

C

acetone
67-64-1

acetone

D

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
at 70℃; for 17h; Mechanism; Rate constant; Thermodynamic data; var. of nitroxide, solvent, temp., EA, ΔH(excit.), ΔS(excit.);A 96%
B 82%
C 100%
D 15%
4-(bromomethylene)-2-(tert-butylthio)-1,3-dithiolylium bromide
71988-81-3

4-(bromomethylene)-2-(tert-butylthio)-1,3-dithiolylium bromide

A

4-(bromomethylene)-1,3-dithiolane-2-thione
71988-82-4

4-(bromomethylene)-1,3-dithiolane-2-thione

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
for 12h; Ambient temperature;A 100%
B n/a
2-(Di-tert-butylamino)-1,3-di-tert-butyl-2,4,4-dimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

2-(Di-tert-butylamino)-1,3-di-tert-butyl-2,4,4-dimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

A

2-(tert-Butylamino)-1,3-di-tert-butyl-2,4,4-trimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

2-(tert-Butylamino)-1,3-di-tert-butyl-2,4,4-trimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
In acetonitrile for 0.0833333h; Heating;A 100%
B n/a
2--1,3-di-tert-butyl-2,4,4-dimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

2--1,3-di-tert-butyl-2,4,4-dimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

A

2-(Trimethylsilylamino)-1,3-di-tert-butyl-2,4,4-trimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

2-(Trimethylsilylamino)-1,3-di-tert-butyl-2,4,4-trimethyl-1,3,2,4-diazaphosphasiletidinium-iodid

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
In acetonitrile for 0.0833333h; Heating;A 100%
B n/a

A

B

Conditions
ConditionsYield
With diisobutylaluminium hydride In pentane at 25℃; for 0.5h;A n/a
B 100%
Conditions
ConditionsYield
With 15-crown-5; cesium fluoride In 1,2-dimethoxyethane at -18 - 20℃; for 1h;100%

A

1-Methyl-2-cyclopenten-1-ol

1-Methyl-2-cyclopenten-1-ol

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With Hoveyda-Grubbs catalyst second generation at 20℃; for 0.75h; Neat (no solvent); Inert atmosphere;A 100%
B n/a
With C35H46Cl2N2ORu In benzene-d6 at 60℃; Catalytic behavior; Reagent/catalyst; Sealed tube;
t-butyl bromide
507-19-7

t-butyl bromide

tri-tert-butyl phosphine
13716-12-6

tri-tert-butyl phosphine

4,8,12-trioxatriangulenium tetrakis[3,5-bis(trifluoromethyl)phenyl]-borate

4,8,12-trioxatriangulenium tetrakis[3,5-bis(trifluoromethyl)phenyl]-borate

A

C19H9BrO3

C19H9BrO3

B

isobutene
115-11-7

isobutene

C

C32H12BF24(1-)*C12H27P*H(1+)

C32H12BF24(1-)*C12H27P*H(1+)

Conditions
ConditionsYield
In acetonitrile at 20℃;A 100%
B n/a
C 100%
tert-butyl methyl ether
1634-04-4

tert-butyl methyl ether

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
at 220℃; under 1200.12 Torr;99.95%
98.4%
shaped catalyst (68percent SiO2, 21percent Al2O3, 11percent MgO, 0.11percent Na2O) at 164 - 250℃; under 5250.53 Torr; for 4000h; Conversion of starting material;
4,4'-dihydroxy-3,3',5,5'-tetra-tert-butylbiphenyl
128-38-1

4,4'-dihydroxy-3,3',5,5'-tetra-tert-butylbiphenyl

A

4,4'-Dihydroxybiphenyl
92-88-6

4,4'-Dihydroxybiphenyl

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With methanesulfonic acid In isopar-G (hydrocarbons C10-C11); toluene at 150℃; for 2h;A 99%
B n/a
tris(1-pyrrolidinyl)(tert-butyl)phosphazide

tris(1-pyrrolidinyl)(tert-butyl)phosphazide

A

tris(1-pyrrolidinyl)(amino)phosphonium tetrafluoroborate

tris(1-pyrrolidinyl)(amino)phosphonium tetrafluoroborate

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With tetrafluoroboric acid In methanol; water at -78 - 20℃; for 2h;A 99%
B n/a
3-acetoxyacetonyl tert-butyl trithiocarbonate
72030-06-9

3-acetoxyacetonyl tert-butyl trithiocarbonate

A

4-(acetoxymethyl)-1,3-dithiole-2-thione
71988-79-9

4-(acetoxymethyl)-1,3-dithiole-2-thione

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With toluene-4-sulfonic acid In acetic acid; trifluoroacetic acid 1. warming, 30 min; 2. heating, 30 min;A 98%
B n/a
2-Amino-4-benzylamino-4,6,6-trimethyl-cyclohex-2-ene-1,1,3-tricarbonitrile
80372-21-0

2-Amino-4-benzylamino-4,6,6-trimethyl-cyclohex-2-ene-1,1,3-tricarbonitrile

A

3-Amino-4-[1-benzylamino-eth-(Z)-ylidene]-2-cyano-pent-2-enedinitrile
80372-33-4

3-Amino-4-[1-benzylamino-eth-(Z)-ylidene]-2-cyano-pent-2-enedinitrile

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
In xylene for 1h; Heating;A 98%
B n/a
triisopropylsilanol
17877-23-5

triisopropylsilanol

(2-methylallyl )triisopropylsilane
321887-70-1

(2-methylallyl )triisopropylsilane

A

hexaisopropyldisiloxane

hexaisopropyldisiloxane

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With scandium tris(trifluoromethanesulfonate) In acetonitrile at 20℃; for 1h;A 98%
B n/a
C11H24O2

C11H24O2

A

isobutene
115-11-7

isobutene

B

trimethyleneglycol
504-63-2

trimethyleneglycol

Conditions
ConditionsYield
With A35 resin acid at 100℃; for 2h; Temperature; Reagent/catalyst;A n/a
B 98%
2,6-dimethyl-4-tert-butylphenol
879-97-0

2,6-dimethyl-4-tert-butylphenol

A

2.6-dimethylphenol
576-26-1

2.6-dimethylphenol

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
aluminum oxide; nickel(II) sulphate In various solvent(s) at 305℃; Product distribution; fixed, quartz powder bed tubular reactor; gaseous phase in N2 flow; varied: temperature 280 to 330 deg C; N2 flow; quartz powder/catalyst ratio; residence time; substrates other alkylated phenols too;A 97.5%
B n/a
butene-2
107-01-7

butene-2

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
at 450℃; under 1125.11 Torr; Reagent/catalyst; Pressure; Temperature; Inert atmosphere;97.4%
at 200 - 380℃; Umlagerung in Gegenwart verschiedener Katalysatoren;
2-methylallyllithium
61777-16-0

2-methylallyllithium

A

1,3-dilithio-2-methylenepropane
53721-69-0

1,3-dilithio-2-methylenepropane

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
at 135℃; for 24h; Yield given;A n/a
B 97%
triisopropylsilanol
17877-23-5

triisopropylsilanol

(2-methylallyl)-dimethylvinylsilane
1351415-92-3

(2-methylallyl)-dimethylvinylsilane

A

1,1-dimethyl-3,3,3-triisopropyl-1-vinyldisiloxane
1351415-84-3

1,1-dimethyl-3,3,3-triisopropyl-1-vinyldisiloxane

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With scandium tris(trifluoromethanesulfonate) In acetonitrile at 20℃; for 1h;A 97%
B n/a
dibutylbis(2-methylallyl)germane
87513-88-0

dibutylbis(2-methylallyl)germane

C32H74O13Si8

C32H74O13Si8

A

di(n-butyl)germasilsesquioxane

di(n-butyl)germasilsesquioxane

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With scandium tris(trifluoromethanesulfonate) In toluene at 20℃; for 2h;A 97%
B n/a
tert-butyl alcohol
75-65-0

tert-butyl alcohol

A

2-methyl-propan-1-ol
78-83-1

2-methyl-propan-1-ol

B

water
7732-18-5

water

C

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
aluminum oxide at 315.546℃; under 11103.3 Torr;A 1.4%
B 1.1%
C 96.4%
2-methyl-propan-1-ol
78-83-1

2-methyl-propan-1-ol

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
BASF AL3996 at 300℃; under 760.051 Torr; Product distribution / selectivity;96%
With BASF A13996R at 325℃; Flow reactor;95%
at 340℃; under 780.078 Torr; Catalytic behavior; Temperature; Pressure; Reagent/catalyst; Inert atmosphere;94.35%
triisobutylindium
6731-23-3

triisobutylindium

A

indium
7440-74-6

indium

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
In decalin byproducts: isobutane; pyrolysis in decalin under dry and deoxygenated N2 (140°C, 24 h); GLC anal. of org. products;A >99
B 96%
di(2-methylallyl)diethylgermane

di(2-methylallyl)diethylgermane

C28H64O13Si8

C28H64O13Si8

A

C60H136GeO26Si16

C60H136GeO26Si16

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With scandium tris(trifluoromethanesulfonate) In toluene at 20℃; for 2h;A 96%
B n/a
1,3-Diamino-2,6,6-tricyan-3,5,5-trimethyl-cyclohex-1-en
80372-13-0

1,3-Diamino-2,6,6-tricyan-3,5,5-trimethyl-cyclohex-1-en

A

2,4-Diamino-1,1,3-tricyan-penta-1,3-dien
80372-25-4

2,4-Diamino-1,1,3-tricyan-penta-1,3-dien

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
In decalin for 1h; Heating;A 95%
B n/a
2-Amino-4,6,6-trimethyl-4-methylamino-cyclohex-2-ene-1,1,3-tricarbonitrile
80372-17-4

2-Amino-4,6,6-trimethyl-4-methylamino-cyclohex-2-ene-1,1,3-tricarbonitrile

A

3-Amino-2-cyano-4-[1-methylamino-eth-(Z)-ylidene]-pent-2-enedinitrile
80372-29-8

3-Amino-2-cyano-4-[1-methylamino-eth-(Z)-ylidene]-pent-2-enedinitrile

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
In xylene for 1h; Heating;A 95%
B n/a
tri(tert-butyl)phosphite
15205-62-6

tri(tert-butyl)phosphite

acrylic acid
79-10-7

acrylic acid

A

di-tert-butyl phosphite
13086-84-5

di-tert-butyl phosphite

B

3-(di-tert-butoxyphosphoryl)propionic acid

3-(di-tert-butoxyphosphoryl)propionic acid

C

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
In dichloromethane for 2h; Heating;A 95%
B n/a
C n/a
1,1,1,5,5,5-hexamethyl-3-trimethylsiloxy-3-hydroxytrisiloxane
17477-97-3

1,1,1,5,5,5-hexamethyl-3-trimethylsiloxy-3-hydroxytrisiloxane

(2-methylallyl)-dimethylvinylsilane
1351415-92-3

(2-methylallyl)-dimethylvinylsilane

A

1,1,1,5,5-pentamethyl-5-vinyl-3,3-bis(trimethylsiloxy)-trisiloxane
1351415-83-2

1,1,1,5,5-pentamethyl-5-vinyl-3,3-bis(trimethylsiloxy)-trisiloxane

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With scandium tris(trifluoromethanesulfonate) In acetonitrile at 20℃; for 1h;A 95%
B n/a
triisopropylsilanol
17877-23-5

triisopropylsilanol

2-methyl a l l y l t r i s-(trimethylsiloxy)silane
37611-52-2

2-methyl a l l y l t r i s-(trimethylsiloxy)silane

A

1,1,1-trimethyl-5,5,5-triisopropyl-3,3-bis(trimethyl-siloxy)trisiloxane
1351415-86-5

1,1,1-trimethyl-5,5,5-triisopropyl-3,3-bis(trimethyl-siloxy)trisiloxane

B

isobutene
115-11-7

isobutene

Conditions
ConditionsYield
With scandium tris(trifluoromethanesulfonate) In acetonitrile at 20℃; for 1h;A 95%
B n/a
3,4-Dimethylphenol
95-65-8

3,4-Dimethylphenol

isobutene
115-11-7

isobutene

2-(1,1-dimethylethyl)-4,5-dimethylphenol
1445-23-4

2-(1,1-dimethylethyl)-4,5-dimethylphenol

Conditions
ConditionsYield
With sulfuric acid at 65℃; under 1034.3 Torr; for 3h;100%
With sulfuric acid at 70℃;
sulfuric acid at 65℃; under 1520.1 Torr;
With sulfuric acid at 65 - 70℃; for 2h;114.1 g
methyl (2S,3R)-2-(benzyloxycarbonylamino)-3-hydroxybutyrate
57224-63-2

methyl (2S,3R)-2-(benzyloxycarbonylamino)-3-hydroxybutyrate

isobutene
115-11-7

isobutene

N-benzyloxycarbonyl-O-tert-butylthreonine methyl ester
52785-41-8

N-benzyloxycarbonyl-O-tert-butylthreonine methyl ester

Conditions
ConditionsYield
With sulfuric acid In dichloromethane at 0℃; for 48h;100%
With sulfuric acid In dichloromethane for 72h; Ambient temperature;75%
With sulfuric acid In dichloromethane
propargyl alcohol
107-19-7

propargyl alcohol

isobutene
115-11-7

isobutene

1-Bromo-2-methyl-2-(2-propyn-1-yloxy)propane
118616-26-5

1-Bromo-2-methyl-2-(2-propyn-1-yloxy)propane

Conditions
ConditionsYield
With N-Bromosuccinimide at 0℃; for 1h;100%
With N-Bromosuccinimide In dichloromethane 1.) -20 deg C, 2 h, 2.) r.t., 15 h;80%
methanol
67-56-1

methanol

pyridine-2-selenenyl bromide
91491-61-1

pyridine-2-selenenyl bromide

isobutene
115-11-7

isobutene

2-(2-Methoxy-2-methyl-propylselanyl)-pyridine
96818-34-7

2-(2-Methoxy-2-methyl-propylselanyl)-pyridine

Conditions
ConditionsYield
at 25℃; for 2h;100%
(S)-2-chloropropanoic acid
29617-66-1

(S)-2-chloropropanoic acid

isobutene
115-11-7

isobutene

(S)-tert-butyl 2-chloropropanoate
101617-24-7

(S)-tert-butyl 2-chloropropanoate

Conditions
ConditionsYield
With hydrogen cation100%
With hydrogen cation93%
With sulfuric acid In dichloromethane at 20℃; for 48h;73%
(E)-ethyl 4-hydroxybut-2-enoate
10080-68-9

(E)-ethyl 4-hydroxybut-2-enoate

isobutene
115-11-7

isobutene

ethyl 4-tert-butoxycrotonate
124155-67-5

ethyl 4-tert-butoxycrotonate

Conditions
ConditionsYield
With sulfuric acid In dichloromethane for 36h; Ambient temperature;100%
O,O′-diacetyl L-tartaric acid
51591-38-9

O,O′-diacetyl L-tartaric acid

isobutene
115-11-7

isobutene

O,O′-diacetyl di-tert-butyl L-tartrate
117384-47-1

O,O′-diacetyl di-tert-butyl L-tartrate

Conditions
ConditionsYield
With sulfuric acid In dichloromethane at -15 - 20℃; for 72h;100%
cumenyl chloride
934-53-2

cumenyl chloride

isobutene
115-11-7

isobutene

(3-chloro-1,1,3-trimethylbutyl)benzene
84803-23-6

(3-chloro-1,1,3-trimethylbutyl)benzene

Conditions
ConditionsYield
With 2,6-di-tert-butyl-pyridine; boron trichloride In various solvent(s) at -80℃; for 0.666667h;100%
zinc chloride diethyl ether In dichloromethane at -78℃; for 4h;71%
(2R,3S)-2-Methoxymethoxy-3-((3S,8S,9S,10R,13S,14S,17R)-3-methoxymethoxy-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)-butyraldehyde
90830-69-6

(2R,3S)-2-Methoxymethoxy-3-((3S,8S,9S,10R,13S,14S,17R)-3-methoxymethoxy-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)-butyraldehyde

isobutene
115-11-7

isobutene

(4R,5R,6S)-5-Methoxymethoxy-6-((3S,8S,9S,10R,13S,14S,17R)-3-methoxymethoxy-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)-2-methyl-hept-1-en-4-ol
131434-15-6

(4R,5R,6S)-5-Methoxymethoxy-6-((3S,8S,9S,10R,13S,14S,17R)-3-methoxymethoxy-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)-2-methyl-hept-1-en-4-ol

Conditions
ConditionsYield
With tin(IV) chloride In dichloromethane at -78℃; for 5h;100%
2-oxo-3-(ethoxycarbonyl)-3,4-dihydro-β-carboline
106544-20-1

2-oxo-3-(ethoxycarbonyl)-3,4-dihydro-β-carboline

isobutene
115-11-7

isobutene

2,2-dimethyl-5-(ethoxycarbonyl)-4,5,6,11b-tetrahydroisoxazolidino<2,3-a>-β-carboline
99708-07-3

2,2-dimethyl-5-(ethoxycarbonyl)-4,5,6,11b-tetrahydroisoxazolidino<2,3-a>-β-carboline

Conditions
ConditionsYield
In toluene at 120℃; under 750.06 - 6750.5 Torr; for 4h;100%
(E)-4-Methyl-6-trimethylsilanyl-hex-4-enal
80399-40-2

(E)-4-Methyl-6-trimethylsilanyl-hex-4-enal

isobutene
115-11-7

isobutene

geranyltrimethylsilane
80399-43-5

geranyltrimethylsilane

Conditions
ConditionsYield
With Wittig100%
3-cyclohexyl-D-alanine
58717-02-5

3-cyclohexyl-D-alanine

isobutene
115-11-7

isobutene

(R)-2-Amino-3-cyclohexyl-propionic acid tert-butyl ester
193286-94-1

(R)-2-Amino-3-cyclohexyl-propionic acid tert-butyl ester

Conditions
ConditionsYield
With sulfuric acid In 1,4-dioxane100%
isobutene
115-11-7

isobutene

polyisobutylene, Mn 5200, cationic polymerization

polyisobutylene, Mn 5200, cationic polymerization

Conditions
ConditionsYield
With Acetyl bromide; MeCOBr*2AlBr3 In dichloromethane at -78℃; for 0.333333h; Polymerization;100%
isobutene
115-11-7

isobutene

polyisobutylene, Mn 41900, cationic polymerization

polyisobutylene, Mn 41900, cationic polymerization

Conditions
ConditionsYield
With aluminum tri-bromide; 2,4,6-Me3C6H2COBr*2AlBr3; Mesitoyl bromide In hexane at -78℃; for 0.333333h; Polymerization;100%
isobutene
115-11-7

isobutene

polyisobutylene, Mn 132000, cationic polymerization

polyisobutylene, Mn 132000, cationic polymerization

Conditions
ConditionsYield
With Acetyl bromide; MeCOBr*2AlBr3; 2,3-dibromo-5,6-dicyano-1,4-benzoquinone In hexane at -78℃; for 0.333333h; Polymerization;100%
isobutene
115-11-7

isobutene

1-benzyloxycarbonyl-4-keto-L-proline
64187-47-9

1-benzyloxycarbonyl-4-keto-L-proline

(2S)-4-oxo-1-phenylmethoxycarbonylpyrrolidine-2-carboxylic acid tert-butyl ester
147489-27-8

(2S)-4-oxo-1-phenylmethoxycarbonylpyrrolidine-2-carboxylic acid tert-butyl ester

Conditions
ConditionsYield
With sulfuric acid In dichloromethane for 12h; Cooling with ice;100%
With sulfuric acid In dichloromethane at 20℃; for 16h;80%
With sulfuric acid In dichloromethane at 20℃; for 16h;80%
isobutene
115-11-7

isobutene

polyisobutylene; monomer: isobutylene

polyisobutylene; monomer: isobutylene

Conditions
ConditionsYield
With tetrachloromethane; triisobutylaluminum; titanium tetrachloride In toluene at 30℃; Polymerization;100%
2-hydroxyphenyl benzoate
5876-92-6

2-hydroxyphenyl benzoate

isobutene
115-11-7

isobutene

2-tert-butoxyphenyl benzoate
136864-81-8

2-tert-butoxyphenyl benzoate

Conditions
ConditionsYield
With trifluorormethanesulfonic acid In dichloromethane at -50 - -45℃; for 2.5h;100%
With trifluorormethanesulfonic acid70%
7,7-diphenyl-6-heptenoic acid
122213-92-7

7,7-diphenyl-6-heptenoic acid

isobutene
115-11-7

isobutene

tert-butyl 7,7-diphenylhept-6-enoate
1038793-13-3

tert-butyl 7,7-diphenylhept-6-enoate

Conditions
ConditionsYield
With sulfuric acid In dichloromethane at 20℃;100%
isobutene
115-11-7

isobutene

polyisobutylene, Mw 285000, Mw/Mn 2.4; monomer(s): isobutylene

polyisobutylene, Mw 285000, Mw/Mn 2.4; monomer(s): isobutylene

Conditions
ConditionsYield
With 1,2-C6F4(B(C(C6F5)2)2 In hexane at -78℃; for 1h;100%
isobutene
115-11-7

isobutene

polyisobutylene, Mw 195000, Mw/Mn 3.2; monomer(s): isobutylene

polyisobutylene, Mw 195000, Mw/Mn 3.2; monomer(s): isobutylene

Conditions
ConditionsYield
With 1,2-C6F4(B(C(C6F5)2)2 In hexane at -78℃; for 1h;100%
isobutene
115-11-7

isobutene

polyisobutylene, Mw 132000, Mw/Mn 5.7; monomer(s): isobutylene

polyisobutylene, Mw 132000, Mw/Mn 5.7; monomer(s): isobutylene

Conditions
ConditionsYield
With 1,2-C6F4(B(C(C6F5)2)2 In hexane at -78℃; for 1h;100%
isobutene
115-11-7

isobutene

polyisobutylene, Mw 140000, Mw/Mn 3.8; monomer(s): isobutylene

polyisobutylene, Mw 140000, Mw/Mn 3.8; monomer(s): isobutylene

Conditions
ConditionsYield
With 1,2-C6F4(B(C(C6F5)2)2 In hexane at -78℃; for 1h;100%
isobutene
115-11-7

isobutene

polyisobutylene, Mw 257000, Mw/Mn 2.0; monomer(s): isobutylene

polyisobutylene, Mw 257000, Mw/Mn 2.0; monomer(s): isobutylene

Conditions
ConditionsYield
With 1,2-C6F4(B(C(C6F5)2)2 In hexane at -78℃; for 1h;100%

115-11-7Related news

Polymerization of ISOBUTYLENE (cas 115-11-7) and copolymerization of ISOBUTYLENE (cas 115-11-7) with isoprene promoted by methylalumoxane07/21/2019

Methylalumoxane (MAO) is an active pre-catalyst for the polymerization of isobutylene and the copolymerization of isobutylene with isoprene at ambient temperature. The absence of any proton-containing substances suggests that the solvent dichloromethane reacts with the MAO forming the active cat...detailed

Quest for pore size effect on the catalytic property of defect-engineered MOF-808-SO4 in the addition reaction of ISOBUTYLENE (cas 115-11-7) with ethylene glycol07/19/2019

In this article, we use defect engineering approach to fine-tune the pore size of MOF-808-SO4. A series of defective MOF-808-SO4 with different pore size were prepared by varying the amount of isophthalic acid as the defective ligand during the synthesis. We obtained a linear correlation between...detailed

Aqueous gelcasting of solid-state-sintered SiC ceramics with the addition of the copolymer of ISOBUTYLENE (cas 115-11-7) and maleic anhydride07/16/2019

As a nontoxic and eco-friendly gelling agent, the copolymer of isobutylene and maleic anhydride (PIBM) was successfully used for aqueous gelcasting of dense solid-state-sintered SiC (S-SiC) ceramics. We acquired low-viscosity SiC-B4C-C slurry with an ultrahigh solid loading of 55 vol% through a ...detailed

Effect of Si/Al ratio of high-silica HZSM-5 catalysts on the prins condensation of ISOBUTYLENE (cas 115-11-7) and formaldehyde to isoprene07/15/2019

A series of HZSM-5 catalysts with different Si/Al ratio were prepared and characterized with various characteristic methods XRD, BET, NH3-TPD, FT-IR spectra of adsorbed pyridine, etc. The effect of Si/Al ratio of HZSM-5 catalysts on the prins condensation of isobutylene and formaldehyde to isopr...detailed

Addition and abstraction kinetics of H atom with propylene and ISOBUTYLENE (cas 115-11-7) between 200 and 2500 K: A DFT study07/14/2019

The rate coefficients for the reactions of hydrogen (H) atom with propylene and isobutylene were studied at M06-2X/6-31+G(d,p) and MPWB1K/6-31+G(d,p) level of theories between 200 and 2500 K. The possible mechanism for the reactions of propylene and isobutylene with H atom were examined. The rat...detailed

Direct amination of ISOBUTYLENE (cas 115-11-7) over zeolite catalysts with various topologies and acidities07/13/2019

The atomically economic and green chemical reaction of direct amination of isobutylene to tert-butylamine, particularly under the relative mild reaction conditions available for future industrial use, was carried out over zeolite catalysts possessing different topological structures, from one di...detailed

Thermodynamic study of direct amination of ISOBUTYLENE (cas 115-11-7) to tert-butylamine07/12/2019

On basis of thermodynamic empirical equations, the thermodynamic parameters for the direct amination of isobutylene to tert-butylamine, an atomically economic and green chemical reaction, were calculated. In particular, the equilibrium conversion of isobutylene under various reaction conditions ...detailed

A wood-rot fungus-mediated production of ISOBUTYLENE (cas 115-11-7) from isobutanol07/11/2019

Generally, isobutylene is produced by petroleum-derived chemical processes, but manufacturing methods using renewable sources, such as biomass, have been considered because of limited amounts of fossil fuel and environmental issues. In this study, isobutylene was converted from isobutanol throug...detailed

115-11-7Relevant articles and documents

Alkylperoxy and Alkyl Radicals. 5. Infrared Spectra and Ultraviolet Photolysis of t-C4H9O2 Radicals in Argon plus Oxygen Matrices

Chettur, G.,Snelson, A.

, p. 5873 - 5875 (1987)

tert-Butyl radicals formed by the pyrolysis of azoisobutane were isolated in matrices of Ar + 10percent 16O2 and Ar + 5percent 16O2 + 5percent 18O2.IR spectra of the resulting trapped species were obtained before and after irradiation of the matrices with a medium-pressure Hg arc lamp.In the 1200-200-cm-1 spectral range, nine absorption bands were observed and assigned to the tert-butylperoxy radical.A summary of the known vibration frequencies assigned to primary, secondary, and tertiary alkylperoxy radical centers is presented.

Key Roles of Lewis Acid-Base Pairs on ZnxZryOz in Direct Ethanol/Acetone to Isobutene Conversion

Sun, Junming,Baylon, Rebecca A. L.,Liu, Changjun,Mei, Donghai,Martin, Kevin J.,Venkitasubramanian, Padmesh,Wang, Yong

, p. 507 - 517 (2016)

The effects of surface acidity on the cascade ethanol-to-isobutene conversion were studied using ZnxZryOz catalysts. The ethanol-to-isobutene reaction was found to be limited by the secondary reaction of the key intermediate, acetone, namely the acetone-to-isobutene reaction. Although the catalysts with coexisting Br?nsted acidity could catalyze the rate-limiting acetone-to-isobutene reaction, the presence of Br?nsted acidity is also detrimental. First, secondary isobutene isomerization is favored, producing a mixture of butene isomers. Second, undesired polymerization and coke formation prevail, leading to rapid catalyst deactivation. Most importantly, both steady-state and kinetic reaction studies as well as FTIR analysis of adsorbed acetone-d6 and D2O unambiguously showed that a highly active and selective nature of balanced Lewis acid-base pairs was masked by the coexisting Br?nsted acidity in the aldolization and self-deoxygenation of acetone to isobutene. As a result, ZnxZryOz catalysts with only Lewis acid-base pairs were discovered, on which nearly a theoretical selectivity to isobutene (~88.9%) was successfully achieved, which has never been reported before. Moreover, the absence of Br?nsted acidity in such ZnxZryOz catalysts also eliminates the side isobutene isomerization and undesired polymerization/coke reactions, resulting in the production of high purity isobutene with significantly improved catalyst stability (2% activity loss after 200 h time-on-stream). This work not only demonstrates a balanced Lewis acid-base pair for the highly active and selective cascade ethanol-to-isobutene reaction but also sheds light on the rational design of selective and robust acid-base catalyst for C-C coupling via aldolization reaction.

A combined experimental and theoretical study of the homogeneous, unimolecular decomposition kinetics of 3-chloropivalic acid in the gas phase

Chuchani,Rotinov,Andres,Domingo,Safont

, p. 1869 - 1875 (2001)

Decomposition kinetics of 3-chloropivalic acid in the gas phase were determined in a static system over the temperature and pressure ranges of 380.5-430.1 °C and 43-120 Torr, respectively. The reaction, in vessel seasoned with allyl bromide, and in the presence of free-radical suppresser toluene, is homogeneous, unimolecular, and follows a first-order rate law. The rate coefficients are given by the following equation: log k1 (s-1) = (12.42 ± 0.36) - (205.8 ± 4.7) kJ mol-1(2.303RT)-1. The reaction mechanism for the formation of isobutene, hydrogen chloride, and carbon dioxide has been theoretically characterized. The theoretical study, at MP2/6-31G** computational level, points out that the molecular mechanism corresponds to a concerted and highly synchronous process yielding the products. An analysis of bond orders and NBO charges shows that the polarization of the C-Cl breaking bond can be considered the driving force for this fragmentation process. The rate coefficients obtained from experimental data and theoretical calculations are in good agreement.

A Fourier-transform Infrared and Catalytic Study of the Evolution of the Surface Acidity of Zirconium Phosphate following Heat Treatment

Busca, Guido,Lorenzelli, Vincenzo,Galli, Paola,Ginestra, Aldo La,Patrono, Pasquale

, p. 853 - 864 (1987)

The surface acidity of zirconium phosphate at different stages of dehydration and heat treatments has been studied by Fourier-transform infrared spectroscopy of adsorbed pyridine, acetonitrile and acetone and by catalytic cativity in the isomerization of but-1-ene.Broensted-acidic surface POH and P(OH)2 groups are identified -1, respectively> whose strenght increases slightly on bulk dehydration.They are thought to be responsible for the activity in but-1-ene isomerization, which also increases during condensation to pyrophosphate.Lewis-acidic sites of medium-high strenght have also been found, and responsible for the formation of chemisorbed forms of pyridine (ν8a = 1610 cm-1), acetonitrile -1> and acetone -1>.Surface ZrOH groups are also detected on the layered ZrP2O7 surface.The results illustrate the role of exposed planes, both parallel and perpendicular to the layered structure.

Investigations into the origin of the remarkable catalytic performance of aged H-ferrierite for the skeletal isomerization of 1-butene to isobutene

Lee, Song-Ho,Shin, Chae-Ho,Hong, Suk Bong

, p. 200 - 211 (2004)

The catalytic properties of the proton form of six different 10-ring zeolites (clinoptilolite, ferrierite, ZSM-22, SUZ-4, ZSM-57, and ZSM-5), together with the dealuminated analogs of some of these materials prepared via oxalic acid treatment, are compared in the skeletal isomerization of 1-butene. While the pore shape of 10-ring channels in this series of medium-pore zeolites was found to be the key parameter substantially governing the isomerization activity, the catalytic data obtained from two H-ferrierites with similar Si/Al ratios but different crystal sizes reveal that the rate of coke formation on this particular zeolite structure, as well as its isobutene selectivity, can differ significantly according to the zeolite crystal size. The overall results of our study strongly suggest that the remarkable isobutene selectivity of aged H-ferrierite is a consequence of pore mouth shape catalysis over the Bronsted acid sites located near the 10-ring pore mouths with a suitable degree of ellipticity, which may come not only from the unique geometrical constraints imposed by the dual pore system of this particular zeolite, but also from its behavior of being normally synthesized with a submicrometer crystal size.

-

Schultz,Kistiakowsky

, p. 395,396 (1934)

-

A Kinetic Study of the Thermal Decarboxylation of α,α-Difluoro β-Lactones

Ocampo, Rogelio,Dolbier Jr., William R.,Bartberger, Michael D.,Paredes, Rodrigo

, p. 109 - 114 (1997)

The rates of thermolysis of α,α-difluoro β-lactones 1, leading to CO2 and 1,1-difluoro olefins, have been obtained in the gas phase and in solution, and the activation parameters are reported. Ab initio calculations on the fluoro and nonfluorinated βlactone systems are also reported. The gas-phase kinetic and theoretical results are discussed in terms of a probable concerted, asynchronous, nonpolar mechanism, whereas the solution kinetics, which include extensive solvent effect studies, are discussed in terms of a polar mechanism which probably involves formation of a zwitterionic intermediate.

Production of isobutylene from acetone over micro–mesoporous catalysts

Ponomareva,Mal’tseva,Maerle,Rodionova,Pavlov,Dobryakova,Belova,Ivanova

, p. 253 - 258 (2016)

The production of isobutylene from acetone over micro–mesoporous catalysts with different mesopore contents, which have been prepared using hydrothermal recrystallization of mordenite (MOR) zeolite modified with cesium acetate by incipient wetness impregnation, has been studied. It has been shown that cesium is inserted into the cation positions during the modification, at the same time the number of Br?nsted acid sites in the samples decreased. It has been found that an increase in the content of mesopores in the catalyst leads to an increase in the initial rates of acetone conversion and isobutylene formation as a result of removing diffusion limitations. Br?nsted acid sites have been shown to be preferable for the selective production of isobutylene from acetone. Micro–mesoporous materials operate more stably as compared to microporous materials.

The Elimination Kinetics of 2-Bromo-3-Methylbutyric Acid in the Gas Phase

Chuchani, Gabriel,Dominguez, Rosa M.

, p. 85 - 88 (1995)

The kinetics of 2-bromo-3-methylbutyric acid in the gas phase was studied over the temperature range of 309.3 - 357.0 deg C and pressure range of 15.5 - 100.0 torr.This process, in seasoned static reaction vessels and in the presence of the free radical i

-

Margerum et al.

, p. 1549,1551 (1959)

-

Enhancement of catalytic wet air oxidation of tert-amyl methyl ether by the addition of Sn and CeO2 to Rh/Al2O3 catalysts

Cuauhtémoc,Del Angel,Torres,Angeles-Chavez,Navarrete,Padilla

, p. 180 - 187 (2011)

The Rh and Rh-Sn supported catalyst on γ-Al2O3 and γ-Al2O3-CeO2 (loading 1, 5 and 20 Ce wt%) were characterized by means of electron microscopy (TEM), temperature programmed reduction (TPR), Fourier transformed infrared of CO adsorption (FTIR-CO) and X-ray photoelectron spectroscopy (XPS). The catalysts were tested in the catalytic wet air oxidation of an aqueous solution of 227 ppm of TAME and 1 g/L of catalyst (120 °C and 10 bar of oxygen partial pressure). The rhodium monometallic catalysts showed an increase in the activity with the load of cerium oxide in the catalyst. The coexistence of Rh°/Rh δ+ and Ce4+/Ce3+ redox couples facilitates the activation of TAME and hence the catalytic activity and selectivity to mineralization. The addition of Snδ+ enhances the activity and selectivity; this is explained by assuming that Sn δ+ acts as Lewis acid sites trapping the TAME molecules for further oxidation on rhodium metal particles.

-

White,Field

, p. 2148,2151, 2152 (1975)

-

Stepwise mechanism of formal 1,5-sigmatropic rearrangement of dimethyl 3,3-dialkyl-3H-pyrazole-4,5-dicarboxylates

Majchrzak, Michael W.,Jefferson, Elizabeth,Warkentin, John

, p. 2449 - 2451 (1990)

-

Direct conversion of bio-ethanol to propylene in high yield over the composite of In2O3 and zeolite beta

Xue, Fangqi,Miao, Changxi,Yue, Yinghong,Hua, Weiming,Gao, Zi

, p. 5582 - 5590 (2017)

A series of In2O3-beta composites with different contents of zeolite beta were prepared by the deposition-precipitation method, followed by calcination at 700 °C, and their catalytic performance in the conversion of ethanol to propylene (ETP) was investigated. The physicochemical properties of the as-synthesized materials were characterized by XRD, N2 adsorption, SEM, NH3-TPD, CO2-TPD and a probe reaction. The combination of In2O3 and zeolite beta improves the propylene yield significantly. The optimal result was observed for the composite with a beta content of 20-50%, which gave ca. 50% yield of propylene. The role of beta in the In2O3-beta composite catalyst is to promote the conversion of the intermediate of acetone to propylene via an additional reaction pathway, which accounts for the superior propylene yield of the In2O3-beta composite in comparison with In2O3 (ca. 32%). The proximity of these two components (In2O3 and zeolite beta) plays a crucial role in achieving a high yield of propylene for the ETP reaction.

Factors affecting the selective isomerization of n-butene into isobutene over ferrierite catalysts

Meriaudeau,Tuan, Vu A.,Hung, Le N.,Naccache,Szabo

, p. 329 - 332 (1997)

-

CHLOROTRIMETHYLSILANE-PHENOL AS A MILD DEPROTECTION REAGENT FOR THE TERT-BUTYL BASED PROTECTING GROUPS IN PEPTIDE SYNTHESIS

Kaiser, Emil,Tam, James P.,Kubiak, Teresa M.,Merrifield, R. B.

, p. 303 - 306 (1988)

Efficient deprotection of the tertbutyl urethane group by 1 M Me3SiCl- 1 M and 3 M-phenol reagents is described.

Catalytic dehydrogenation of isobutane over a Ga2O3/ZnO interface: Reaction routes and mechanism

Wang, Guowei,Li, Chunyi,Shan, Honghong

, p. 3128 - 3136 (2016)

In this work, physical mixtures of ZnO and Ga2O3, even with a small amount of Ga2O3, were found to exhibit greatly enhanced catalytic performance for isobutane dehydrogenation compared to their individual components, namely solely ZnO or Ga2O3. The activity test results under different packing patterns indicated that, the interface between the two component oxides played a crucial role in improving the dehydrogenation performance. Moreover, consistent with the highest dehydrogenation reactivity, the largest activation energy for isobutane desorption over ZnO-Ga2O3 was determined using an isobutane-TPD test. The observed synergistic effect of ZnO and Ga2O3 could be understood as being that, Lewis acid sites provided by Ga2O3 promoted the heterolytic cleavage of C-H bonds in isobutane over ZnO, thereby increasing the isobutane conversion. On the surface of ZnO-Ga2O3, a double-site adsorption of isobutane was further speculated through FT-IR spectra analysis, and one-step decomposition was probably the actual reaction pathway of isobutane. In addition, from understanding that catalyst deactivation was caused by highly graphitized coke deposition, the deactivated catalyst was regenerated through air combustion, and good catalyst stability was demonstrated through continuous reaction-regeneration cycles.

[(≡SiO)TaV (=CH2)Cl2], the first tantalum methylidene species prepared and identified on the silica surface

Chen, Yin,Callens, Emmanuel,Abou-Hamad, Edy,Basset, Jean-Marie

, p. 3 - 6 (2013)

A novel surface tantalum methylidene [(≡SiO)TaV (=CH 2)Cl2] was obtained via thermal decomposition of the well-defined surface species [(≡SiO)TaVCl2Me 2]. This first surface tantalum methylidene ever synthesized has been fully characterized and the kinetics of the a-hydrogen abstraction reaction has also been investigated in the heterogeneous system.

Selective Isomerization of Butene to Iso-Butene

Cheng, Zheng Xing,Ponec, Vladimir

, p. 607 - 616 (1994)

Selective isomerization of butene to iso-butene has been studied with pure and variously modified alumina as catalysts.Results can be self-consistently eplained by concluding that (i) the molecular mechanism operates and requires Lewis acid sites, the presence and quality of which can be modulated by heat treatment in hydrogen, by surface modification with halogens, and by application of certain catalytic poisons, and (ii) the bimolecular mechanism is related to the Broensted acid sites and is stimulated, as expected, by increased pressure of n-butene.

Selective Oxidative Dehydrogenation of Isobutane over a Y2O3-CeF3 Catalyst

Zhang, Wei-De,Tang, Ding-Liang,Zhou, Xiao-Ping,Wan, Hui-Lin,Tsai, K. R.

, p. 771 - 772 (1994)

The multi-valence anion modified complex catalyst Y2O3-CeF3 was found to be selective for the oxidative dehydrogenation of isobutane to isobutene at a relatively high conversion.

EXTRACTION OF STANDARD HELMHOLTZ FUNCTIONS FROM AFFINITY RATE DATA

Garfinkle, Marvin

, p. 717 - 726 (1985)

An extrapolation procedure to extract standard Helmholtz functions from empirical kinetic data without reference to reaction mechanisms has been developed using an analytical description of the affinity decay rate.

The Study of CrOx-Containing Catalysts Supported on ZrO2, CeO2, and CexZr(1–x)O2 in Isobutane Dehydrogenation

Bugrova,Mamontov

, p. 143 - 149 (2018)

Olefin hydrocarbons are valuable raw materials for petrochemical and polymer manufacturing. Highly effective, but toxic chromium-containing catalytic materials are the most widely used catalysts to obtain olefins in industry. In this regard, the urgent challenge to increase the efficiency of oil processing is to develop the catalysts with low content of harmful active component. In the present study, the catalysts with low chromium content (1 theoretical monolayer = 5 Cr atoms per nm2 of support) were synthesized by incipient wetness impregnation of the supports (Al2O3, ZrO2, CeO2, and CexZr(1–x)O2). The samples obtained were characterized by low-temperature nitrogen adsorption, X-ray diffraction and H2-temperature-programmed reduction methods. The catalytic properties of the catalysts were tested in isobutane dehydrogenation reaction. It was shown that the state of chromium on the surface is different over different supports. For the CrOx/CeO2 catalyst, the formation of Cr2O3 particles with low activity in the dehydrogenation reaction was observed. For other samples, a highly disperse X-ray amorphous state of chromium was characteristic. The catalyst based on CexZr(1–x)O2 was the most active in isobutane dehydrogenation reaction due to possible stabilization of chromium as Cr(V) state.

-

Odioso et al.

, p. 209,211 (1961)

-

Petrow

, (1954)

Jones

, p. 1877 (1938)

Insights into the doping effect of rare-earth metal on ZnAl2O4 supported PtSn catalyzed isobutane dehydrogenation

Liu, Jianfeng,Zhou, Wei,Jiang, Dongyu,Wang, Dong,Wu, Wenhai,Wang, Yue,Ma, Xinbin

, p. 58 - 65 (2020/04/27)

Isobutane dehydrogenation is a vital route for the production of isobutene, an important substance for methyl tert-butyl ether. However, the reaction is typically performed at relatively low pressure and high temperature, resulting in a facilitated coke formation. Here, we used rare-earth metals (Y, La, Ce) as dopants to modify the ZnAl2O4 support and studied their effects on Pt-Sn catalyzed dehydrogenation of isobutane. Combining the experimental and theoretical results, it is demonstrated that while Y and La tend to incorporate into the matrix of ZnAl2O4, separate CeO2 phase could be easily formed on ZnAl2O4 surface, leading to a decrease in both amount and strength of the Lewis acid sites. And for the La-ZnAl2O4, because of the large local deformation, oxygen vacancy can be readily formed, and results in a lot acid sites in the subsurface layer available for reactions. Deactivation rates of the catalysts in isobutane dehydrogenation is found to linearly correlate with the Lewis acid amounts over the modified supports. Compared with the catalysts of Pt-Sn/ZnAl2O4, Pt-Sn/La-ZnAl2O4 and Pt-Sn/Y-ZnAl2O4, Pt-Sn/Ce-ZnAl2O4 exhibits superior catalytic performance due to the low coke contents and high Pt dispersion. These results may provide additional insights on the design and optimization of isobutane dehydrogenation catalysts by tailoring the composition and structure of oxide supports.

METHOD FOR DEHYDRATING ALCOHOLS TO OBTAIN OLEFINS, INVOLVING A STEP OF CATALYST SELECTIVATION

-

Paragraph 0055-0077, (2021/03/19)

The invention relates to a process for dehydrating alcohols to olefins, comprising a reaction step and a catalyst selectivation step.

Synthesis and catalytic application of nanorod-like FER-type zeolites

Dai, Weijiong,Deng, Xin,Guan, Naijia,Li, Landong,Ruaux, Valérie,Tai, Wenshu,Valtchev, Valentin,Wu, Guangjun

, p. 24922 - 24931 (2021/11/27)

Nanosize dimensions have an important impact on zeolite properties and catalytic performance in particular. Herein, we develop a direct synthesis route to obtain a nanosized nanorod-like ferrierite (FER) zeolite with the assistance of ammonium fluoride (NH4F) and employing a conventional structure-directing agent (pyrrolidine). The resultant nanorod-like FER zeolite crystals exhibit a greatly reduced diffusion path along the c-axis. The physicochemical properties of nanorod-like FER and its conventional micronsized plate-like counterpart were analyzed by N2 adsorption-desorption, 27Al, 1H, 29Si MAS NMR, NH3-TPD, and in situ D3-acetonitrile and pyridine adsorption followed by FTIR. The nanorod-like FER zeolite possesses superior characteristics in terms of a larger external area, better accessibility to the acid sites, and a larger number of pore mouths per unit crystal surface than the micron-sized counterpart synthesized without NH4F. The improved properties provide the nanorod-like FER zeolite with high selectivity and low deactivation rates in 1-butene skeletal isomerization. The thermogravimetry analysis (TGA) of the coke amounts revealed a better capability of coke tolerance of the nanorod-like FER zeolite. The in situ ultraviolet-visible (UV/Vis) and Fourier transform infrared spectroscopy (FTIR) spectroscopy investigations of the organic intermediates formed on FER zeolite catalysts during the catalytic reaction further verified the enhanced catalytic activity and stability of the nanorod-like FER zeolite.

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