24 results about "Methanethiol" patented technology

An oral care composition is provided and includes a natural flavor extract, a sulfur source such as dimethyl disulfide, a stannous ion source, and a soluble metal ion source that prevents the formation of methyl mercaptan. The natural flavor extract may contain dimethyl disulfide as an impurity. The soluble metal ion source may include a metal salt, a metal oxide, or a combination thereof, and the soluble metal ion source may include a copper ion source, a silver ion source, a zinc ion source, or combinations thereof.

The invention discloses a preparation process of 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid, and relates to the technical field of preparation of inorganic compounds. The invention relates to a preparation process of 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid, which comprises the following steps: reacting 3-chloro-2-methylaniline with hydrochloric acid and sodium methyl mercaptide to form an intermediate C1, reacting with acetyl chloride, catalyzing with anhydrous aluminum trichloride to form an intermediate C2, reacting with hydrogen peroxide and sodium hypochlorite to form an intermediate C4, and reacting with sodium chloride to form the 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid. The 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid is obtained after the reaction is completed.

The invention discloses a recombinant O-acetyl-L-homoserine mercaptotransferase mutant, a recombinant genetically engineered bacterium and application of the recombinant O-acetyl-L-homoserine mercaptotransferase mutant and the recombinant genetically engineered bacterium. The mutant is obtained by performing single mutation or multiple mutation on the 33rd site, the 55th site, the 237th site and the 238th site of an amino acid sequence shown in SEQ ID NO.2. The method has the beneficial effects that the method has more efficient catalytic activity and stronger substrate tolerance, has the advantages of mild conditions, less discharge of three wastes, high selectivity and high product yield when being used for catalyzing OAH and sodium methyl mercaptide to synthesize L-methionine, and has a wide development space in the aspect of industrial production of L-methionine.

The invention relates to the technical field of catalytic synthesis, in particular to an oxidation catalyst, a preparation method and application thereof and a methanesulfonic acid preparation method. The oxidation catalyst comprises a carrier and an active component loaded on the carrier, the active component is prepared from OsO4, PtO2, MoO, TiO2 and V2O5; the carrier comprises Al2O3 modified by a Ce element; on the basis that the weight percentage of the carrier is 100%, the active components comprise the following components in percentage by weight: 0.06%-4% of OsO4, 0.01%-3% of PtO2, 0.005%-2% of MoO, 0.05%-1% of TiO2 and 0.06%-2% of V2O5. The oxidation catalyst is used for catalyzing sodium methyl mercaptide to oxidize and prepare methanesulfonic acid, the reaction efficiency is high, the reaction condition is mild, and the atom economy is very high.

An oral care composition is provided and includes hops acid, a tin ion source, a sulfur source, and a soluble metal salt that prevents the formation of methyl mercaptan. The soluble metal salt may include a copper salt, a silver salt, a zinc salt, or combinations thereof. The hops acid may be from a hops extract. The sulfur source may be an impurity, and the soluble metal salt may prevent the formation of unacceptable off-notes, which may be produced in the composition under reducing conditions.

The application discloses a catalyst for catalyzing COS / H2S to synthesize methyl mercaptan and a preparation method thereof, and belongs to the technical field of catalysts. The catalyst is spherical alumina, and the preparation method comprises the following steps: dissolving alumina precursors, a sulfate and a precipitating agent in water to obtain a mixed solution, and performing a hydrothermal reaction by heating; and after the hydrothermal reaction is completed, cooling, filtering, washing, drying and calcining are performed to obtain the spherical alumina catalyst. The spherical alumina catalyst is prepared by a hydrothermal and calcination method, the catalyst has a unique microsphere structure and acid-base sites, can provide more active centers and a better reaction environment, greatly enhances the activity and selectivity of COS / H2S in synthesizing methyl mercaptan, and thus has a better catalytic effect in a reaction related to COS / H2S cooperative removal and resource synthesis of methyl mercaptan.

This invention relates to the field of herbicide technology, specifically to a method for preparing a sulfadiazine intermediate, comprising: (1) reacting 3,4-dichloronitrobenzene, methyl cyanoacetate, and a first base in the presence of a first solvent to obtain a compound of formula (II); (2) reacting the compound of formula (II) with sodium methanethiol in the presence of a second solvent to obtain a compound of formula (III); and (3) reacting the compound of formula (III) with a second base and hydrogen peroxide in the presence of a third solvent to obtain the sulfadiazine intermediate of formula (I). This method has the advantages of mild reaction conditions, high reaction yield and purity, and low cost, making it suitable for industrial production.

The application discloses a methanethiol synthesis catalyst with a wide hydrogen sulfide to methanol ratio and a preparation method thereof. The catalyst comprises the following components in parts of mass: 1-10 parts of magnesium oxide, 60-80 parts of aluminum oxide, 10-25 parts of potassium tungstate and 2-10 parts of vanadium pentoxide. The catalyst can keep high activity, high selectivity and long service life in a wide methanethiol ratio range, and has wide application value.

This invention relates to the field of adsorption and filtration material preparation technology, specifically a multifunctional composite air purification filter material and its preparation method. It includes the following steps: S1, a method for preparing transition metal ion-modified carbon; S2, a filter material composite method. Compared with existing technologies, this invention provides a multifunctional composite air purification filter material and its preparation method. Modified activated carbon can remove sulfur and nitrogen compounds and odorous gases that are difficult to adsorb conventionally through ion network interaction. The use of copper sulfate, zinc sulfate, and 2-aminoimidazole synergistically can effectively complex and adsorb odorous gases with low olfactory thresholds, such as trimethylamine and methanethiol, which are difficult to treat. This modified activated carbon is then embedded between an activated manganese catalytic framework cloth and an electrostatic meltblown cloth, maintaining an extremely low filter material thickness, thus achieving efficient removal of formaldehyde, particulate matter, and odors from a single filter material.

The invention relates to a bacterium enzyme composite deodorant and application thereof, which can effectively improve the digestive function of the gastrointestinal tract of a piglet to promote the growth of the piglet, obviously reduce the emission of volatile malodorous substances in excrement, and provide a new feed additive for healthy breeding of the piglet and improvement of the breeding environment. Wherein the compound bacteria are prepared by uniformly mixing lactobacillus plantarum, saccharomyces cerevisiae and bacillus licheniformis according to the weight ratio of 3: 2: 1, the compound enzyme is prepared by uniformly mixing protease and amylase according to the weight ratio of 1: 25, and the compound bacteria and the compound enzyme are uniformly mixed according to the weight ratio of 2: 1. As a feed additive, the feed additive can significantly improve the average daily gain of piglets, improve the digestive function of intestinal tracts of the piglets, improve the growth performance of the piglets, reduce the feed-gain ratio, effectively reduce the pH value and the water content of excrement and reduce emission of volatile malodorous substances such as ammonia gas, hydrogen sulfide and methyl mercaptan, and is an efficient, green, ecological and safe feed additive. The method has popularization and application value in various pig farms.

This invention discloses a halitosis-eliminating toothpaste containing galangal extract and its preparation process. The toothpaste comprises a galangal volatile oil-cyclodextrin inclusion complex and / or positively charged nanoparticles loaded with galangal flavonoids, as well as a pH adjuster, sodium bicarbonate. Ethyl p-methoxycinnamate and ethyl cinnamate in the galangal volatile oil undergo a Michael addition reaction with methanethiol under weakly alkaline conditions, rapidly neutralizing existing odor-causing sulfides. The positively charged nanoparticles are electrostatically adsorbed onto the tooth surface, slowly releasing flavonoids and providing long-lasting inhibition of odor-producing bacteria. The preparation process includes gel preparation, graded pre-dispersion, sequential addition and mixing, and vacuum degassing, further specifying the preparation methods of the inclusion complex and nanoparticles. This invention is free of metal ions and chemical bactericides, achieving immediate neutralization and long-lasting antibacterial synergy, and is characterized by safety, stability, naturalness, and high efficiency in eliminating halitosis.

An oral care composition is provided and includes hops acid, a tin ion source, a sulfur source, and a soluble metal salt that prevents the formation of methyl mercaptan. The soluble metal salt may include a copper salt, a silver salt, a zinc salt, or combinations thereof. The hops acid may be from a hops extract. The sulfur source may be an impurity, and the soluble metal salt may prevent the formation of unacceptable off-notes, which may be produced in the composition under reducing conditions.

The invention discloses a deodorization composition for long-acting inhibition of sulfur-nitrogen odor and a preparation method thereof. The composition comprises the following components in parts by weight: 1-5 parts of an oxidizing agent, 10-40 parts of an acid neutralizer, 5-20 parts of a pH buffer agent, 80-120 parts of an adsorbent, 5-20 parts of an inclusion agent and 1-2 parts of a bacteriostatic agent. Through cooperation of multiple mechanisms of oxidation, neutralization, adsorption, inclusion and bacteriostasis, efficient and lasting removal of ammonia gas, methyl mercaptan and other composite odors is realized. The composition is in the form of solid powder and is suitable for hygienic products such as paper diapers and pet padding. The preparation method comprises the following steps: crushing and sieving the components in a dry environment, uniformly mixing a small amount of components with the same amount of other components, and gradually mixing the mixture with the rest components in batches until all the components are fully and uniformly mixed. The composition is low in cost, good in stability and high in deodorization rate, and has a good industrial application prospect.

The invention provides a chromatographic analysis method of methyl mercaptan. The chromatographic analysis method comprises the following steps: providing a liquid methyl mercaptan sample under the pressure of 1-3 MPa; a liquid methyl mercaptan sample is conveyed into a gas chromatograph through a high-pressure liquid sample injection valve and is separated and detected through two analysis paths, wherein the first analysis path comprises that the vaporized sample sequentially enters a first chromatographic column and a second chromatographic column for limiting flow to be separated; the second analysis path comprises the following steps: intercepting fractions flowing out of the first chromatographic column from the vaporized sample entering the first chromatographic column according to a preset time window through a center cutting technology in a microflow plate center cutting system, and then cutting the fractions into a third chromatographic column for re-separation; the first chromatographic column is a non-polar capillary column or a weak-polar capillary column, the second chromatographic column is an empty white chromatographic column, and the third chromatographic column is a polar or medium-polar capillary column. The invention provides complete off-line analysis for high-purity liquid methyl mercaptan samples from sample stabilization to efficient quantitative and qualitative analysis and separation of impurities.

The utility model provides a kind of methyl mercaptan synthesis device, using self-made catalyst in fixed bed reactor catalysis hydrogen sulfide and methanol reaction to obtain methyl mercaptan. After methanol is vaporized, it is mixed with hydrogen sulfide and enters preheater to preheat, then enters reactor, and mixed gas passes through the reactor filled with catalyst from top to bottom, and methyl mercaptan is obtained under certain temperature and pressure. The reaction principle of the device is simple, has raw material price advantage, and the catalyst obtained can be used to catalyze the reaction of methanol and hydrogen sulfide to generate methyl mercaptan, with the advantages of high selectivity and stability, and the device can realize continuous production.

The application provides a freezing history indicator, which comprises a diaryl viologen and a guanidine macrocycle, the diaryl viologen has a structure as shown in the figure, R is a methanethiol group, a methoxy group, a nitrogen-nitrogen dimethyl group or other electron-donating groups, and the guanidine macrocycle has a structure as shown in the figure; the freezing history indicator has low cost, can indicate the sample alone after being packaged, and has obvious fluorescence color contrast before and after freezing; the fluorescence color remains unchanged after the indicator is recovered to normal from freezing, and the indicator does not recover to the normal state before freezing, so that the display effect is good, and whether the substance has experienced the freezing process can be clearly indicated; the technology is based on materials with low cost, small dosage, easy preparation and portable labels, and can be used for following the product to detect the freezing history of the whole logistics process.

To enhance flavor sensitivity.SOLUTION: A method for improving flavor sensitivity of a subject, the method comprising reducing amounts of Methanethiol (MTH) and Dimethyl sulfide (DMS) in an oral cavity of the subject, where the flavor sensitivity is flavor sensitivity to a flavor derived from at least one selected from the group consisting of Dipropyl disulfide (DPDS), Methional (MTNA), Dimethyl disulfide (DMDS) and 2-Methyl-3-furanthiol (MFT).SELECTED DRAWING: None

The utility model relates to the technical field of metering tank, concretely is a kind of product metering tank for sodium methanethiol solution production, including bottom plate, the upper surface of bottom plate is fixedly connected with nitrogen storage tank and control switch, the inner wall of bottom plate is fixedly connected with metering tank main body, the top of metering tank main body is fixedly connected with metering pump, the top of metering tank main body is fixedly connected with driving motor, the inner wall of metering tank main body is fixedly connected with bearing and annular pipe.The product metering tank for sodium methanethiol solution production, driving motor output power is rotated by being set to drive stirring rod, the structure can break the solid particle precipitate in sodium methanethiol solution in real time, avoid solution layering, significantly improve solution overall uniformity, solve the problem " because of solution unevenness leads to measurement error " from source, provide basic guarantee for subsequent metering pump accurate measurement, substantially improve the measurement accuracy of sodium methanethiol solution.

The invention relates to a preparation method of a modified gamma-Al2O3 catalyst and a synthesis method for converting dimethyl sulfide into methyl mercaptan. The catalyst is prepared by adopting an equivalent-volume impregnation method, taking VIB, VIIB, VIII and IIB group metal oxides as active components, taking alkali metal, lanthanide series metal and nonmetal oxides as assistants, loading the active components and the assistants on a gamma-Al2O3 carrier treated by organic phosphonic acid (HEDP (hydroxyethylidene diphosphonic acid) and ATMP (amino trimethylene phosphonic acid)), enabling the metal loading capacity to be 0.5-20wt%, drying and roasting. According to the catalyst, the dimethyl sulfide conversion rate (greater than or equal to 60%) and the methyl mercaptan selectivity (greater than or equal to 95%) are remarkably improved through the synergistic effect of acidic site regulation and metal active components. The invention also discloses the optimal process conditions of the catalytic reaction: the reaction temperature is 230-400 DEG C, the pressure is 0-5.0 MPa, the air speed is 50-150h <-1 >, and the molar ratio of H2S to dimethyl sulfide is 1-8. The technology solves the problem of high-value utilization of dimethyl sulfide byproducts, has the characteristics of carbon deposition resistance, sulfur deposition resistance and high stability, and is suitable for industrial production.

This invention relates to a method for controlling a chemical process, wherein the chemical process is one or more of the preparation of methanol, hydrogen sulfide, methanethiol, hydrogen cyanide, acrolein, 3-methylthiopropional, 5-(2-methylthioethyl)-hydantoin, methionine, methionine salts, and methionine derivatives, comprising the steps of: a) providing a training set TS1, wherein the training set TS1 includes process values ​​PV1 and PV2 associated with each other, and / or laboratory values ​​LV1 and PV2 associated with each other; b) training a processing unit based on the training set TS1 of step a) to identify one or more measured process variables and at least one... The correlation model between process variables is used to develop a calibration function CF1 for the calibrated soft sensor based on the identified correlation model. c) Predict at least one operating parameter for the chemical process as an approximation of LV1 and / or PV1. d) Calculate the deviation as the difference between the predicted operating parameter and the corresponding laboratory value LV1 and / or treatment value PV1 of the training set TS1 in step a). e) If the deviation calculated in step d) exceeds a threshold, proceed to step f); otherwise, proceed to step g). f) Recalibrate the soft sensor in step b). g) Write the predicted at least one operating parameter into the DCS. h) Repeat steps c) to g).

An oral care composition is provided and includes a natural flavor extract, a sulfur source such as dimethyl disulfide, a stannous ion source, and a soluble metal ion source that prevents the formation of methyl mercaptan. The natural flavor extract may contain dimethyl disulfide as an impurity. The soluble metal ion source may include a metal salt, a metal oxide, or a combination thereof, and the soluble metal ion source may include a copper ion source, a silver ion source, a zinc ion source, or combinations thereof.