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| | 4-Bromobenzocyclobutene Basic information |
| | 4-Bromobenzocyclobutene Chemical Properties |
| Boiling point | 118-119 °C(Press: 20 Torr) | | density | 1.470 g/mL at 25 °C | | refractive index | n20/D1.589 | | Fp | 100℃ | | storage temp. | 2-8°C | | form | liquid | | Appearance | Colorless to light yellow Liquid | | InChI | InChI=1S/C8H7Br/c9-8-4-3-6-1-2-7(6)5-8/h3-5H,1-2H2 | | InChIKey | GMHHTGYHERDNLO-UHFFFAOYSA-N | | SMILES | C12C(CC1)=CC=C(Br)C=2 | | CAS DataBase Reference | 1073-39-8(CAS DataBase Reference) |
| Hazard Codes | Xn | | Risk Statements | 22-51 | | WGK Germany | 3 | | Storage Class | 10 - Combustible liquids | | Hazard Classifications | Acute Tox. 4 Oral |
| | 4-Bromobenzocyclobutene Usage And Synthesis |
| Chemical Properties | colorless or light yellow liquid | | Uses | 4-Bromobenzocyclobutene is used in organic synthesis. It is also used in the production of pharmaceuticals, agrochemicals, and other fine chemicals.
| | Application | 4-Bromobenzocyclobutene is a polymer precursor reagent used in the preparation of photoresist materials. 4-Bromobenzocyclobutene can undergo a Heck reaction with acrylic acid to produce 4-acryloylbenzocyclobutene (BCB-V-COOH), subsequently, BCB-V-COOH is copolymerised with dibenzocyclobutene-bis-divinylsiloxane (DVS-b-BCB) in varying ratios to produce the oligomer BCB-SO-COOH. These oligomers are graft-modified with propylene oxide methyl acrylate to yield BSA resin, which can be mixed with a photoinitiator to formulate photoresist. The introduction of BCB significantly improves the thermal stability and dielectric properties of the BSA resin[6]. Furthermore, it can be used to prepare 4-vinylbenzocyclobutene via a coupling reaction with vinyl bromide under nickel catalysis, and this can be further converted into poly(4-vinylbenzocyclobutene)[7]. | | Reactions |
The bromine atom in 4-bromobenzocyclobutene is highly reactive and can undergo various chemical reactions, such as substitution, elimination, and coupling reactions.
| | Hazard | 4-Bromobenzocyclobutene is harmful if taken by mouth and can cause acute toxicity. | | Materials Uses | A low curing temperature (210 °C), low water absorption, rapid curing, and low viscosity make dry-etchable BCB the material of choice for a variety of applications in gallium arsenide integrated circuits. Its low dielectric constant, loss, and moisture uptake, and its high compatibility with copper make BCB highly suitable for integrating passive components such as filters and op amps (operational amplifiers). | | Synthesis | The general procedure for the synthesis of 4-bromobenzocyclobutene from benzocyclobutene is as follows: first, α-chloro-o-xylene 1 is subjected to a pyrolysis reaction at about 800 °C and 0.5 mbar to produce benzocyclobutene 2 in 45% yield. Subsequently, benzocyclobutene 2 was dissolved in acetic acid and reacted with a mixture of bromine and iodine at room temperature for selective bromination to give 4-bromobenzocyclobutene 3. 3 was dissolved in toluene and a slightly molar excess of 1,4-dihydro-1,4-epoxynaphthalene 4 was added and reacted for 20 hr at 220° C. to give the Diels-Alder addition product 5 as a pure inner/outer in 80% yield mixture, which was a colorless crystalline substance. -yl)-5,12-dihydroanthracene 7. After recrystallization of compound 7 with o-dichlorobenzene, the dehydrogenation reaction was carried out by treatment with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in boiling o-xylene. After repeated vacuum sublimation purification, orange-red crystals of 2-(anthracen-2-yl)tetraphenyl 8 were finally obtained in 75% yield. All intermediates were characterized by 1H NMR, 13C NMR spectroscopy and mass spectrometry. Compound 8 was characterized by UV-visible spectroscopy. | | References | [1] Chemistry - A European Journal, 2017, vol. 23, # 54, p. 13445 - 1345
[2] Patent: US2008/214838, 2008, A1. Location in patent: Page/Page column 2-3
[3] Tetrahedron, 1965, vol. 21, p. 245 - 254
[4] Journal of the Chemical Society [Section] B: Physical Organic, 1969, p. 12 - 15
[5] Patent: EP2236500, 2010, A1. Location in patent: Page/Page column 21
[6] Wei Chen. (2025). Benzocyclobutenyl Silicone-Acrylic Resin: A Photo/Thermal Curing Hybrid Structure for High-Performance Photoimageable Dielectrics. Macromolecular Rapid Communications, 46 21. https://doi.org/10.1002/marc.202500411
[7] Takeshi Endo. (1995). Synthesis of poly(4-vinylbenzocyclobutene) and its reaction with dienophiles. Journal of Polymer Science Part A: Polymer Chemistry, 33 4, 707–715. https://doi.org/10.1002/pola.1995.080330412
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| | 4-Bromobenzocyclobutene Preparation Products And Raw materials |
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