9003-31-0 Usage
Description
Polyisoprene is the polymer known as natural rubber, although it can also be manufactured. The natural rubber latex is harvested from the rubber tree, Hevea brasiliensis. This substance has a variety of natural additives, such as proteins and sugars. The polymer from the natural latex is resistant to many solvents and also is easily processed. The synthetic form of this rubber is produced from a pure isoprene solution with a stereospecific isomer to produce the more commonly used cis-l,4 isomer. These rubbers are resistant to abrasion and most solvents and are commercially used in automobile tires, adhesives, and a variety of products that come in close contact with the general public. Their use in baby bottle nipples is a good indication of the extremely low toxicity associated with these elastomers.
Chemical Properties
Different sources of media describe the Chemical Properties of 9003-31-0 differently. You can refer to the following data:
1. Natural rubber is the name applied to the polymer cis-1,4-polyisoprene obtained chiefly from the 4590 RUBBER, NATURAL latex of the Hevea brasiliensis tree.
2. There are two main solvents for rubber: turpentine and
naptha (petroleum). Because rubber does not dissolve easily,
the material is finely divided by shredding prior to immersion.
Natural rubber has been partially replaced by synthetics,
particularly styrene–butadiene, as a generalpurpose
rubber. High resilience, low heat buildup, and
easy processing are particular advantages of natural rubber
when it is often used in blends with synthetic polyisoprene
and other elastomers. Natural rubber, alone and in combination
with neoprene, has been rated highly for resistance to
water, dimethyl sulfoxide, and some alcohols in a comparative
test of glove materials; resistance to other solvents varied
from good to poor. Polyisoprene supports combustion.
Uses
Natural rubber is a vital, strategic, and irreplaceable raw material used in enormous quantities by the commercial, medical, transportation, and defense industries. At least 40,000 different products and over 400 medical devices contain natural rubber.
Production Methods
The latex of natural rubber is obtained from trees (Hevea
brasiliensis); the actual monomer is isopentenyl pyrophosphate
that has been formed by biosynthesis. Natural rubber
contains low-molecular-weight impurities; small amounts of
sugar, fatty acids, proteins, and trace metals all play an
important part in processing.
Depending on the catalyst, rubber may undergo 1,2-; 3,4-;
or 1,4- additional polymerization that leads to several isomeric
structures.
Almost all commercial synthetic polyisoprenes are prepared
from purified isoprene monomer by a solution process.
A stereospecific catalyst, such as an Al–Ti Ziegler type, is
required for direct polymerization to the cis-1,4 isomer.The production of the finished polymer requires two
separate manufacturing processes: (a) formation of the
rawpolymer and (b) conversion of the polymer to the finished
rubber product. The first step is similar to that of plastic
production. Large-scale operations use bulk materials in an
enclosed system.
Definition
The major component of natural rubber, also made synthetically. Forms are stereospecific cis-1,4and trans-1,4-polyisoprene.Both can be produced synthetically by the effect of heat and pressure on isoprene in the presence of stereospecific catalysts. Nat
General Description
Available as part of Negative Photoresist kit 654892
Industrial uses
Rubber is characterized as being a highly elastic or resilient material, and the natural product is obtained mainly as a latex from cuts in the trunks of the Hevea brasiliensis tree. The latex consists of small particles (averaging about 2500 ? units in diameter) of rubber suspended in an aqueous medium (at about 35% solids content). The system also contains about 6 to 8% nonrubber constituents, some of which are emulsifiers, naturally occurring antioxidants, and proteins.Natural rubber is used for making many types of articles. Because of its abrasion-resistant quality and low hysteresis in reinforced compounds, it is used in truck-tire tread stocks and in conveyor belts that which are employed in conveying abrasive material such as coal, crushed rock, ore, and cinders. In large tires, it has found application in carcass compounds because of the tack and building qualities of the raw polymer. It has also been used in carcass compounds because of the low heat buildup (low hysteresis) of the carcass compound vulcanizate during severe service conditions in tire usage.
Check Digit Verification of cas no
The CAS Registry Mumber 9003-31-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 9,0,0 and 3 respectively; the second part has 2 digits, 3 and 1 respectively.
Calculate Digit Verification of CAS Registry Number 9003-31:
(6*9)+(5*0)+(4*0)+(3*3)+(2*3)+(1*1)=70
70 % 10 = 0
So 9003-31-0 is a valid CAS Registry Number.
9003-31-0Relevant articles and documents
Mechanisms of Methylenecyclobutane Hydrogenation over Supported Metal Catalysts Studied by Parahydrogen-Induced Polarization Technique
Salnikov, Oleg G.,Burueva, Dudari B.,Kovtunova, Larisa M.,Bukhtiyarov, Valerii I.,Kovtunov, Kirill V.,Koptyug, Igor V.
, (2022/03/15)
In this work the mechanism of methylenecyclobutane hydrogenation over titania-supported Rh, Pt and Pd catalysts was investigated using parahydrogen-induced polarization (PHIP) technique. It was found that methylenecyclobutane hydrogenation leads to formation of a mixture of reaction products including cyclic (1-methylcyclobutene, methylcyclobutane), linear (1-pentene, cis-2-pentene, trans-2-pentene, pentane) and branched (isoprene, 2-methyl-1-butene, 2-methyl-2-butene, isopentane) compounds. Generally, at lower temperatures (150–350 °C) the major reaction product was methylcyclobutane while higher temperature of 450 °C favors the formation of branched products isoprene, 2-methyl-1-butene and 2-methyl-2-butene. PHIP effects were detected for all reaction products except methylenecyclobutane isomers 1-methylcyclobutene and isoprene implying that the corresponding compounds can incorporate two atoms from the same parahydrogen molecule in a pairwise manner in the course of the reaction in particular positions. The mechanisms were proposed for the formation of these products based on PHIP results.
Study on heteropolyacid-based catalysts with high activity and reusability for isoprene synthesis from formaldehyde and isobutene
Wang, Qingxue,Luo, Xu,Liu, Li,Tao, Shenghui,Xu, Shan
, p. 5371 - 5381 (2021/04/06)
Silica-supported heteropolyacid catalysts with different pore structures were synthesizedviaimpregnation method using silicalite-1 with three-dimensional MFI structure, two-dimensional hexagonal SBA-15 and amorphous silica as supports. Moreover, these catalysts were employed for the gas phase one-step synthesis of isoprene from isobutene and formaldehyde. The result showed that the activity of silicotungstic acid supported on silicalite-1 (SiW/S-1) catalysts was significantly better than that on other supports, which indicates that the three-dimensional MFI structure and suitable pore size of silicalite-1 were more conducive to the production of isoprene. Furthermore, the formation rate of isoprene over 20% SiW/S-1 catalyst reached up to 8.5 times that on the bulk silicotungstic acid catalyst, which could be attributed to the highly dispersed silicotungstic acid and the suitable acidity produced by the strong interaction between silicotungstic acid and silicalite-1. In addition, the 20 wt% SiW/S-1 catalyst exhibited excellent reusability and was reused 10 times without obvious loss of activity.
Piperazine-promoted gold-catalyzed hydrogenation: The influence of capping ligands
Barbosa, Eduardo C. M.,Camargo, Pedro H. C.,Fiorio, Jhonatan L.,Hashmi, A. Stephen K.,Kikuchi, Danielle K.,Rossi, Liane M.,Rudolph, Matthias
, p. 1996 - 2003 (2020/04/22)
Gold nanoparticles (NPs) combined with Lewis bases, such as piperazine, were found to perform selective hydrogenation reactions via the heterolytic cleavage of H2. Since gold nanoparticles can be prepared by many different methodologies and using different capping ligands, in this study, we investigated the influence of capping ligands adsorbed on gold surfaces on the formation of the gold-ligand interface. Citrate (Citr), poly(vinyl alcohol) (PVA), polyvinylpyrrolidone (PVP), and oleylamine (Oley)-stabilized Au NPs were not activated by piperazine for the hydrogenation of alkynes, but the catalytic activity was greatly enhanced after removing the capping ligands from the gold surface by calcination at 400 °C and the subsequent adsorption of piperazine. Therefore, the capping ligand can limit the catalytic activity if not carefully removed, demonstrating the need of a cleaner surface for a ligand-metal cooperative effect in the activation of H2 for selective semihydrogenation of various alkynes under mild reaction conditions.
