Category: 13031-04-4

In homogeneous catalysis, the catalyst is in the same phase as the reactant. The number of collisions between reactants and catalyst is at a maximum.In a patent, 13031-04-4, name is 4,4-Dimethyldihydrofuran-2,3-dione, introducing its new discovery. 13031-04-4

MANUFACTURE OF KETOPANTOLACTONE

A process for the oxidation of pantolactone to ketopantolactone comprises carrying out the oxidation with a periodate in the presence of a ruthenium catalyst, in an aqueous solvent system and in a microwave field. Ketopantolactone is a key intermediate in the manufacture of pantothenic acid, the latter being a member of the B complex vitamins and a constituent of coenzyme A. Asymmetric hydrogenation of ketopantolactone yields (D)(-)-pantolactone, from which pantothenic acid can then be manufactured.

Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.13031-04-4, you can also check out more blogs about13031-04-4

Reference£º
Tetrahydrofuran – Wikipedia,
Tetrahydrofuran | (CH2)3CH2O – PubChem

13031-04-4, 4,4-Dimethyldihydrofuran-2,3-dione is a Tetrahydrofurans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Examples 1-4 [00041] The process of the present invention as set forth in FIG. 1 is typically initiated by dissolving the alpha ketocarbonyl compound and the modifier in vessel (1). The resulting solution contains from about 0.1 wt % to about 100 wt % of the alpha ketocarbonyl compound and from about 1¡Á10-5 wt % to about 0.5 wt % of modifier. [00042] The mass flow is started at the reaction temperature, for example, at 17 C. or 20 C. (Examples 1 and 2, respectively). The above solution containing an alpha ketocarbonyl compound and a modifier is pumped into the fixed bed reactor (2) and contacted with hydrogen to start the hydrogenation reaction. Before catalytic runs, the reactor is flushed with nitrogen. [00043] Subsequently, the content of vessel (1) is continuously pumped into the fixed bed reactor. The solution flow rate is preferably from about 0.1 to about 50 ml/minute, the preferred flow of the alpha ketocarbonyl compound is 2¡Á10-5-2¡Á10-2 mol/gcat/minute. More preferably, the solution flow rate is preferably from about 2.5 to about 10 ml/minute, and the flow of the alpha ketocarbonyl compound is from about 2¡Á10-4-3¡Á10-3 mol/gcat/minute. [00044] The modifier flow rate is preferably from about 2¡Á10-9 to about 2¡Á10-4 mol/gcat/minute, such as, for example, from about 2¡Á10-8 to about 7¡Á10-6 mol/gcat/minute. [00045] Hydrogen is continuously fed into the fixed bed reactor via flow line (3) containing a compressor (4) and a pressure control system (5). The inert gas, e.g. nitrogen, is fed into the reactor (2) via line (7). [00046] The hydrogen flow rate into the reactor is metered and monitored by a rotameter. Suitable hydrogen flow rates are from about 0.0001 mol/minute (2.4 ml/minute) to about 1 mol/minute (24000 ml/minute), for example, from about 5¡Á10-6 to about 10 mol/gcat/minute. [00047] The hydrogenation reaction can be carried out at a relatively low temperature ranging between about -20 C. and about 100 C., the preferred temperature range is from about -10 C. to about 50 C., such as for example from about 0 C. to about 20 C. [00048] The pressure in the reactor is suitably adjusted to between about 2 bar and about 150 bar, preferably from about 40 bar to about 100 bar. [00049] The effluent from the hydrogenation reaction zone is fed over a two-step expansion module (6) to a separator where the alpha hydroxy carbonyl compound is recovered. [00050] The process set forth in FIG. 2 is initiated by dissolving the alpha ketocarbonyl compound and the modifier in vessel (1) or by adding a solution containing the modifier to a liquid alpha ketocarbonyl compound. The resulting solution has the following concentration: [00051] about 0.1 wt % to about 100 wt % of alpha ketocarbonyl compound; and [00052] about 1¡Á10-6 wt % to about 0.5 wt % of modifier. [00053] The reactor vessel (2) is charged with a supercritical solvent via flow line (3) containing a compressor (4) and a pressure control system (5). [00054] The organic flow is started at a reaction temperature of, for example, about 50 C. (Example 3) or 36 C. (Example 4). The solution set forth above is pumped into the fixed bed reactor (2) and contacted with hydrogen to start the hydrogenation reaction. [00055] Subsequently, the content of vessel (1) is continuously pumped into the fixed bed reactor with the same solution flow rate as in the process according to FIG. 1. [00056] The flow rate of the supercritical co-solvent is preferably from about 50 ml/minute to about 5000 ml/minute. [00057] When using a liquid alpha ketocarbonyl compound, the supercritical co-solvent is used with a flow rate of about 50 ml/minute to about 5000 ml/minute. [00058] The modifier flow rate is preferably from about 2¡Á10-11 to about 2¡Á10-4 mol/gcat/min. [00059] Hydrogen is continuously fed into the fixed bed reactor via flow line (7) containing a pressure control system (5). The hydrogen flow rate into the reactor was metered and monitored by a rotameter. [00060] Suitable hydrogen flow rates are from about 0.0001 mol/minute (2.4 ml/minute) to about 1 mol/minute (24000 ml/minute) such as for example from 5¡Á10-6 to about 10 mol/gcat/minute. [00061] The hydrogenation reaction can be carried out at a relatively low temperature ranging between about 20 C. to about 100 C., preferably from about 30 C. to about 60 C., such as for example from about 35 C. to about 50 C. The pressure is suitably adjusted to between about 2 bar to about 150 bar, preferably about 40 bar to about 100 bar., 13031-04-4

As the paragraph descriping shows that 13031-04-4 is playing an increasingly important role.

Reference£º
Patent; Roche Vitamins Inc.; US6646135; (2003); B1;,
Tetrahydrofuran – Wikipedia
Tetrahydrofuran | (CH2)3CH2O – PubChem

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.13031-04-4,4,4-Dimethyldihydrofuran-2,3-dione,as a common compound, the synthetic route is as follows.,13031-04-4

A rhodium catalyst precursor [Rh(COD)Cl]2, a chiral bisphosphine ligand 3 (R1 = Boc), a polyether alkylguanidinium salt ionic liquid [ (PG), CH3 (EO) 16TMG] SO3CH3, ketopantolactone and benzene, the molar ratio of 3 to Rh is 1.1: 1, the mass ratio of ionic liquid to rhodium catalyst precursor is 500: 1, the ratio of ketopantolactone to Rh The molar ratio is 100: 1, the volume ratio of benzene to ionic liquid is 4: 1, the atmosphere is replaced with nitrogen or argon for 4-6 times, and then pressurized with hydrogen to 5.0MPa, the reaction is carried out at 50 for 4 hours and then rapidly cooled After hydrogen was vented, the benzene was removed under reduced pressure and extracted twice with methyl tert-butyl ether. The volume ratio of methyl tert-butyl ether to benzene was 1: 1. The system was split into two phases and was isolated by simple phase separation The upper methyl tert-butyl ether phase containing D-pantolactone was analyzed by gas chromatography. The conversion of ketopantolactone was 77.6%, and the ee value of D-pantolactone was 60.7%. The reaction conditions and procedures were the same as in Example 1 except that the solvent was changed to toluene, the molar ratio of ketopantolactone to Rh was 200: 1, the pressure of hydrogen was 0.1 MPa, the reaction temperature was 25 C, and the reaction time was 2h. Analysis by gas chromatography showed that the conversion rate of ketopantolactone was 97.5% and that of D-pantolactone was 92.2%.

The synthetic route of 13031-04-4 has been constantly updated, and we look forward to future research findings.

Reference£º
Patent; Qingdao University of Science and Technology; Jin Xin; Li Shumei; Cui Feifei; (8 pag.)CN104761518; (2017); B;,
Tetrahydrofuran – Wikipedia
Tetrahydrofuran | (CH2)3CH2O – PubChem

13031-04-4, 4,4-Dimethyldihydrofuran-2,3-dione is a Tetrahydrofurans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

13031-04-4, General procedure: Hydrogenations of ketones at atmospheric H2-pressure wereperformed in a 50-mL three-necked glass reactor at RT and atatmospheric pressure under constant flow of molecular H2 with a volumetric flow rate of 10 mL min-1 (semi-batch hydrogenation). The third opening of the reactor was sealed with a septum which allowed for addition/removal of solutions containing modifier and ketone by the use of a syringe. The stirring rate was set to 500 rpm. Hydrogenations performed at 10 bar H2-pressure were carried out in a 60-mL Hastelloy steel jacketed-reactor connected to a multi-position valve (VICI) which allows for connecting the reactor to the hydrogen and nitrogen reservoirs, and to open it to the atmosphere.The H2-pressure was controlled with a constant pressure regulator (Brooks 5688 Series). The standard reaction temperature (298 K) in the jacket was controlled with a Haake Phoenix (Thermo) water bath. The stirring rate was set to 750 rpm. The general reaction procedure for all hydrogenations was the following: the pre-reduced catalyst (50 mg Pt/Al2O3) was transferred to the reactor und reduced again in situ in 5 ml solvent under constant H2flow for 1 h. Then, the reaction was initiated by addition of modifier and ketone premixed in 5 mL solvent. The conversion and enantioselectivity in the hydrogenation were determined by gas chromatography (GC), using an Agilent Technologies 7890A gas chromatograph equipped with a flame ionisation detector (FID). Samples were injected with a split ratio of20: 1 at an injector temperature of 250C. For GC separation, a chiral capillary column (CP-Chirasil-Dex CB, 25 m length, 0.25 mm internal diameter, 0.25 m film thickness) was used. For the analysis of KPL hydrogenations, the temperature programme started at 80C, increased to 140C at 10C min-1, increased to 180C at 20C min-1, and then held for 2 min. For the analysis of MBF hydrogenations, the temperature programme started at 120C,increased to 180C at 20C min-1, and then held for 2 min. For the analysis of TFAP hydrogenations, the temperature programmestarted at 120C, held for 1 min, increased to 130C at 1C min-1, held for 1 min, increased to 140C at 10C min-1, held for 1 min,increased to 150C at 1C min-1, held for 1 min, and then increased to 180C at 40C min-1. The FID was operated at 300C with con-stant flows of hydrogen as fuel gas (30 mL min-1) and air as oxidant(400 mL min-1). Nitrogen was used as a make-up gas (25 mL min-1)and helium as a carrier gas (constant flow: 1.623 mL min-1). The target analytes could be separated: KPL (retention time 5.84 min,elution temperature 138.4C, (S)-PL (7.38 min, 167.6C), and (R)-PL (7.51 min, 170.2C); MBF (retention time 6.09 min, elutiontemperature 145.5C, (R)-MM (7.38 min, 155.2C), and (S)-MM(7.51, 155.7C); TFAP (retention time 1.75 min, elution temperature 120.8C, (S)-PTFE (10.7 min, 130.0C), and (R)-PTFE (11.1 min,130.1C). Products were identified using enantiopure alcohol products.

As the paragraph descriping shows that 13031-04-4 is playing an increasingly important role.

Reference£º
Article; Holland, Mareike C.; Meemken, Fabian; Baiker, Alfons; Gilmour, Ryan; Journal of Molecular Catalysis A: Chemical; vol. 396; (2015); p. 335 – 345;,
Tetrahydrofuran – Wikipedia
Tetrahydrofuran | (CH2)3CH2O – PubChem