is a chemical substance with black powder particles. Molecular formula Pd, CAS 7440-05-3. Palladium carbon is a catalyst, which is insoluble in all organic solvents and acid solutions. It is made by loading metal palladium onto activated carbon, and its main function is to catalyze the hydrogenation of unsaturated hydrocarbons or CO. Palladium carbon has the characteristics of high hydrogenation reducibility, good selectivity, stable performance, small feed ratio in use, repeatable use and easy recovery. It is widely used in the hydrogenation reduction refining process of petrochemical industry, pharmaceutical industry, electronic industry, spice industry, dye industry and other fine chemicals.
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106 |
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106 |
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m/z |
106 (100.0%), 108 (96.8%), 105 (81.7%), 110 (42.9%), 104 (40.8%), 102 (3.7%) |
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Pd, 100.00 |
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Palladium carbon (Pd/C) is an efficient catalyst supported on activated carbon by palladiu metal. Its unique physical and chemical properties, such as high specific surface area, excellent catalytic activity, and selectivity, make it an indispensable core material in modern chemical industry.
1. Hydrofining
is a key catalyst for hydrogenation desulfurization (HDS), hydrogenation denitrification (HDN), and hydrogenation demetalization (HDM) in petroleum refining. For example, in the process of refining terephthalic acid (PTA), palladiu carbon can efficiently catalyze the hydrogenation reduction of impurities in the oxidation products of xylene, converting 4-carboxybenzaldehyde (4-CBA) into easily separable alcohols, increasing the purity of PTA to over 99.9%, meeting the production needs of polyester fibers.
Data support: Over 80% of the global PTA production capacity adopts palladiu carbon catalytic technology, and a single unit consumes about 5-10 tons of palladiu carbon catalyst per year.
2. Unsaturated hydrocarbon hydrogenation
Palladium carbon exhibits high selectivity in the hydrogenation reactions of olefins and alkynes.
For example, in ethylene production, acetylene can be selectively hydrogenated to ethylene through palladiu carbon catalysis, avoiding excessive hydrogenation to produce ethane and increasing ethylene yield by 15% -20%.
Technical advantages: Compared with traditional Lindra catalysts, palladiu carbon can achieve efficient conversion at low temperatures (50-100 ℃) and low pressures (1-5 MPa), reducing energy consumption by more than 30%.
3. Hydrogenation of aromatic compounds
Palladium carbon can catalyze the hydrogenation of aromatic hydrocarbons such as benzene and naphthalene. For example, in the process of benzene hydrogenation to cyclohexane, palladium carbon catalyst reduces the reaction temperature from 300 ℃ to 150 ℃, the pressure from 10 MPa to 3 MPa, and the selectivity of cyclohexane reaches over 99%.
1. Chiral drug synthesis
The asymmetric hydrogenation reaction catalyzed by palladiu carbon is one of the core technologies for chiral drug synthesis. For example, in the synthesis of the antidepressant paroxetine, palladiu carbon catalyzed asymmetric hydrogenation of ketone compounds produces chiral alcohol intermediates with an enantiomeric excess (ee value) of 99.5%, significantly reducing subsequent separation costs.
Case: After Pfizer adopted palladiu carbon catalytic technology, the annual production of paroxetine increased from 50 tons to 200 tons, and the cost per ton decreased by 40%.
2. Construction of heterocyclic compounds
Palladium carbon can catalyze the formation of C-N and C-O bonds, and construct heterocyclic structures such as indole and pyridine.
For example, in the synthesis of the anti-tumor drug imatinib, palladiu carbon catalyzed coupling reaction of aniline and chloropyridine increased the yield from 60% to 92%, and the reaction time was shortened from 24 hours to 4 hours.
Technological breakthrough: Through the application of nano palladiu carbon catalyst (particle size 2-5 nm), the reaction activity is increased by 3 times and the catalyst dosage is reduced by 80%.
3. Purification of drug intermediates
Palladium carbon can be used to remove toxic groups such as halogens and nitro groups from pharmaceutical intermediates. For example, in the synthesis of the antibiotic ceftriaxone, palladiu carbon catalyzed removal of chlorine atoms from intermediates resulted in an increase in product purity from 95% to 99.9%, meeting FDA standards.
1. Preparation of Semiconductor Materials
The palladium carbon catalytic chemical vapor deposition (CVD) process is the key to preparing high-purity silicon-based thin films. For example, in solar cell coating, palladium carbon catalyzes the decomposition of silane (SiH ₄) to generate uniform and dense amorphous silicon thin films, increasing the photoelectric conversion efficiency by 5% -8%.
Data: The global photovoltaic industry consumes approximately 200 tons of palladium carbon catalysts annually, accounting for over 60% of the electronic industry's usage.
2. Production of conductive paste
Palladium carbon, as a conductive phase additive, can significantly enhance the conductivity and adhesion of silver paste and copper paste. For example, in the manufacturing of touch screen electrodes, adding 0.5% palladium carbon silver paste can reduce the contact resistance to 10 Ω· cm and extend the service life to over 100000 times.
, and can inhibit silver particle aggregation and maintain the stability of the conductive network during high-temperature sintering (300-500 ℃).
Palladium membrane (thickness 0.1-0.5 μ m) is the core material for hydrogen purification. For example, in the production of semiconductor grade hydrogen gas (9N level), palladiu membrane selectively penetrates hydrogen molecules through dissolution diffusion mechanism, which can remove impurities such as CO and CO ₂ to ppb level, meeting the requirements of chip manufacturing.
Market: The global palladiu membrane market size exceeds 500 million US dollars, with an annual growth rate of 12%, mainly used in 12 inch wafer production lines.
1. Waste water treatment
Palladium carbon catalytic hydrogenation technology can efficiently degrade organic pollutants. For example, in the treatment of printing and dyeing wastewater, palladiu carbon catalyzed hydrogenation reduction of nitrobenzene to aniline achieves a COD removal rate of over 95%, and the reaction time is shortened from 72 hours in traditional biological methods to 2 hours.
Case: After adopting palladiu carbon catalytic technology in a chemical industrial park, the cost of wastewater treatment decreased from 50 yuan per ton to 15 yuan, saving over 10 million yuan in annual operating expenses.
2. Waste gas purification
Palladium carbon supported catalyst is the core component of three-way catalyst (TWC) for automobile exhaust.
For example, in National VI standard gasoline vehicles, the conversion efficiency of palladiu carbon catalysis for CO, HC, and NOx reaches 98%, 95%, and 90%, respectively, meeting the emission limit requirements.
Technological trend: With the rise in palladiu prices, the development of palladium rhodium platinum ternary alloy catalysts has become a hot topic in the industry, reducing palladium usage by 30% -50% through synergistic effects.
3. Soil remediation
Palladium carbon catalytic reduction technology can remediate heavy metal contaminated soil. For example, in the remediation of hexavalent chromium contaminated sites, palladiu carbon catalyzed iron powder reduction of Cr (VI) to Cr (III) reduces toxicity by 99% and shortens the remediation cycle from 2 years in traditional chemical methods to 6 months.
1. Hydrogen energy development
Palladium carbon is a key material for proton exchange membrane fuel cells (PEMFC). For example, in the cathodic oxygen reduction reaction (ORR), palladium carbon supported catalysts can increase the power density of the battery to 1.5 W/cm ² and extend its lifespan to over 5000 hours.
Research and development progress: By constructing a palladiu nitrogen carbon (Pd-N-C) single atom catalyst, the ORR activity has been increased by 10 times and the cost has been reduced by 60%.
The palladium carbon catalytic hydrogenation/dehydrogenation reaction is the core of LOHC technology. For example, in the toluene methylcyclohexane system, palladium carbon catalyzed hydrogenation of toluene can store hydrogen gas with an energy density of 6.5 wt% and a dehydrogenation efficiency of 99%, meeting the demand for on-board hydrogen storage.
Market potential: The global LOHC market is expected to grow from $200 million in 2025 to $2 billion in 2030, with a compound annual growth rate of 58%.
Palladium carbon catalyzed lignin depolymerization can produce high value-added chemicals. For example, in the conversion of corn stover, palladium carbon catalyzes the degradation of lignin into phenolic compounds such as vanillin and syringaldehyde, with a yield increase from 10% in traditional acid hydrolysis to 35%.
Environmental benefits: Compared to fossil fuels, biomass routes reduce carbon footprint by 70%, meeting carbon neutrality goals.
, including catalytic method, alkali metal method, electrochemical method, etc.
Catalytic method, also known as catalytic reduction method, refers to a method to obtain palladium carbon compounds by atomic transfer or interatomic interaction of reaction products under the action of catalyst. Generally, the preparation methods of catalytic oxidation are catalytic reduction, ion exchange, catalytic reduction, etc. Generally, catalytic oxidation is carried out by atom transfer of noble metals without solvent and atom to atom interaction and atom transfer under the action of catalyst. The cost of this method is low. However, the palladium based metal atoms cannot completely exchange with other noble metal atoms and exist on the catalyst, which affects the combination between platinum based metal atoms and noble metal atoms and the formation and transfer of compounds.
Alkali metal method is also called alkali metal method. It refers to the method of preparing palladium compounds by chemical reaction of alkali metals and platinum group elements. Alkali metal method, also known as alkaline metallization method, is one of the methods to obtain palladium carbon compounds by reacting precious metal sodium (NaCl) containing a large number of platinum atoms with other metal salts (NaAl) in palladium compounds to convert them into platinum group elements and platinum based compounds. Alkali metal method can produce high purity jewelry without catalyst under mild reaction conditions; However, due to the high chemical reaction temperature (generally 200~300 ℃) and large amount of catalyst (usually accounting for more than 90% of platinum group elements), high purity jewelry body cannot be prepared.
Electrochemical method is a method that uses chemical reaction to make platinum group elements react with catalyst or metal ions to generate palladium oxide. In general, electrochemical method is to use an electrochemical reactor to react metal ions containing platinum (such as Au, Cu, etc.) on the electrode. The catalyst directly participates in the reaction, while platinum based compounds are reduced to platinum compounds due to their strong reducibility, but this reaction will lead to corrosion of platinum based compounds by metal ions, which requires the addition of electrolyte for protection. This method also has two obstacles: low reactant concentration (only 1-3 g/L) and low yield (only about 1%). However, many kinds of palladium compounds can be obtained by this method.
In organic synthesis of palladium carbon compounds, metal ions are generally used as catalysts to generate platinum atoms and palladium atoms through different chemical bonding. Palladium atoms are mainly formed on two side chains of palladium catalyst. In addition, palladium carbon compounds can also react with some metal ions to form other compounds through incomplete reaction with carbon element under reducing conditions, thus preparing other compounds. For example, platinum alkene is reduced to obtain triethanolamine; Ethanolamine was obtained by incomplete reaction of Ptene ethanolamine acrylamide; Palladium alkene was obtained by incomplete reaction of platinum alkene ethanolamine acrylamide; was obtained by incomplete reaction of platinum alkene acrylamide; Pt Pd was obtained by incomplete reaction of Ptene acrylamide. In these reactions, some small products or intermediate products such as palladium platinum enamide acrylamide (PVDF) or aromatic hydrocarbons will also be produced.
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