US2421109A - Method of producing crystals of nordihydroguaiaretic acid - Google Patents

Method of producing crystals of nordihydroguaiaretic acid Download PDF

Info

Publication number
US2421109A
US2421109A US541660A US54166044A US2421109A US 2421109 A US2421109 A US 2421109A US 541660 A US541660 A US 541660A US 54166044 A US54166044 A US 54166044A US 2421109 A US2421109 A US 2421109A
Authority
US
United States
Prior art keywords
nordihydroguaiaretic acid
solvent
water
miscible
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US541660A
Inventor
Adams Joseph
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Minnesota
Original Assignee
University of Minnesota
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Minnesota filed Critical University of Minnesota
Priority to US541660A priority Critical patent/US2421109A/en
Application granted granted Critical
Publication of US2421109A publication Critical patent/US2421109A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
    • C07C37/004—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by obtaining phenols from plant material or from animal material

Definitions

  • My invention has for its object the provision of an industrially practicable method of producing merchantable crystals of the anti-oxidant nordihydroguaiaretic acid.
  • An object and accomplishment of my invention is the production of original crystals of nordihydroguaiaretic acid that are pure and free from odoriferous contaminants, and thus admirably two selective solvents.
  • one is watermiscible; nordihydroguaiaretic acid is readily soluble in it but cannot be crystallized from it.
  • the other solvent is water immiscible but miscible with the first solvent; nordihydroguaiaretic acid is only slightly soluble in it but can be crystallized out of it.
  • the material wherewith my method begins consists of some or all of the woody portions, leaves, stems, flowers, and buds of the so-called creosote bush (botanically named Larrea dwaricata) or, and preferably, an acidulatedalkali or alcoholic extraction thereof.
  • a suitable quantity of the starting material is. digested with a water-miscible solvent (e. g., anhydrous methyl alcohol) that has been ascertained to be a very good solvent for nordihydroguaiaretic acid.
  • a water-miscible solvent e. g., anhydrous methyl alcohol
  • the soluble constituents of the starting material are in solution I dilute the water-miscible solvent with a very much larger (e. g., twenty-five times as large) quantity of a second or water-immiscible solvent (e. g., ethylene dichloride) that has been ascertained tobe one in which nordihydroguaiaretic acid is only slightly soluble, but which is miscible with the first or water-miscible solvent.
  • the insoluble substances in the mixed solvents are now removed, preferably by filtering. to prevent any emulsificationof the solvents in the next step of the method. All of the foregoing preferably is accomplished
  • the mixed solvents are then subjected to vigorous agitation while there is being added thereto an amount of water substantially larger (e. g., four times as large) as the amount of the first or water-miscible solvent.
  • the first or water-miscible solvent is washed from the second or water-immiscible solvent, and such waterimmiscible solvent takes unto itself from said water-miscible solvent certain very finely dispersed particles including nordihydroguaiaretic acid--this transfer of solutes occurring because they are not soluble in the aqueous dilution of the water-miscible solvent.
  • the agitation should be continued long enough to insure complete divorcement of the water-miscible solvent from the water-immiscible solvent. 7
  • the two resultant immiscible liquids are permitted to settleand are then separated.
  • the one of such liquids which includes the second or water-immiscible solvent is then filtered to remove all foreign matter not in, solution.
  • Such liquid is then substantially concentrated, preferably by being heated in vacuo, in sumcient degree (e. g., nearly so that when it is subsequently subjected to controlled cooling and aided by agitation of theliquid, precipitates, first, a resinous red phenolic by-product and, second, a delayed crystal formation of nordihydroguaiaretic acid.
  • the liquid When by continuance of such controlled cool ing the liquid has attained a temperature of approximately F., it preferably is subjected to agitation which aiyls the development and precipitation of a, delayed crystal formation of nordihydroguaiaretic acid. These first crystals of nordihydroguaiaretic acid are removed from the liquid by filtration.
  • Next th liquid is again substantially concentrated (e. g., by 50%) preferably by being heated in vacuo, and is again subjected to controlled cooling to between F. and F., when an.- other precipitation of-the resinous redvphenolic by-product is removed by filtration.
  • controlled cooling of the liquid to approximately 60 F., plus agitation, again causes the formation of a substantial quantity of crystals. These are removed irom the liquid by filtration and dried.
  • methyl alcohol as my water-miscible solvent
  • various other water-miscible monohydroxy or polyhydroxy alcohols such, for examples, as ethyl alcohol, isopropyl alcohol, propylene glycol and ethylene glycol
  • ethylene dichloride as my watch-immiscible solvent
  • the resultant alcoholic sludge is then diluted with 75 gallons of ethylene dichloride.
  • miscible liquids are then violently agitated while 12 gallons of water is added thereto to wash the methyl alcohol from the ethylene dichloride and to transfer from the methyl alcohol to the ethylene dichloride certain finely dispersed particles, including nordihydro uaiaretic acid, which have greatly reduced solubility' in a 20% solution of methyl alcohol in water.
  • the tem erature of the liquids is not permitted to fall below 115 F.
  • the agitation is continued for 20 minutes, the two immiscible liquids resulting from the addition of water and the agitation .(i.
  • the process of producing nordihydroguaiae retlc acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a first solvent selected from the group consisting of water miscible mono and polyhydric low aliphatic alcohols to produce a solution of nordihydroguaiaretic acid, adding to chloride fraction is then filtered. It is then concentrated, by being heated in vacuo, from 75 galions to 40 gallons. Controlled cooling of the concentrated solvent follows. when its temperature reaches 70 F., it is filtered to remove a resinous phenolic fraction.
  • the process of producing nordihydroguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a first solvent selected from the group consisting of water miscible mono and polyhydrlc low aliphatic alcohols to produce a solution of nordihydroguaiaretic acid, adding to said solution-a much greater quantity of a second solvent miscible with said first solvent, said second solvent. being selected from the group consisting of monocyclic aromatic hydrocarbons. and halogenated low aliphatic hydrocarbons, introducing 3.
  • a first solvent selected from the group consisting of water miscible mono and polyhydrlc low aliphatic alcohols
  • the process of producing nordihydroguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a low aliphatic monohydric alcohol to produce a solution of nordihydroguaiaretic acid, adding to said solution-a halogenated low aliphatic hydrocarbon miscible with said alcohol, washing the mixture with water to remove the alcohol, and crystallizing the nordihydroguaiaretic acid from the halogenated hydrocarbon.
  • the process of producing nordihydroguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Larreu. divaricata containing nordihydroguaiaretic acid, with methyl alcohol to produce a solution of nordihydroguaiaretic acid, adding ethylene dichloride to said solution, washing the mixture with water to remove the methyl alcohol and crystallize nordihydroguaiaretic ,acid from the ethylene dichloride.
  • the process 'of producing nordihydroguaiaguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a first solventselected from the group consisting of water miscible mono and polyhydric low aliphatic alcohols to produce a solution of nordihydroguaiaretic acid, adding to said solution a second solvent miscible with said first solvent, said second solvent being selected from the group consisting of monocyclic aromatic hydrocarbons and halogenated low aliphatic hydrocarbons, washing the mixture with water to remove the first solvent, concentrating the second solvent, permitting it to cool to approximately from 70 F. to 80 F., removing a precipitated resinous red phenolic by-product, cooling the second solvent further to approximately 60 F. to crystallize nordihydroguaiaretic acid and removing the nordihydroguaiaretic acid crystals.
  • the process of producing nordihydroguaia- 2 retic acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydro methyl alcohol to produce a solution of nordihydroguaiaretic acid, adding ethylene dichloride to said solution, washing the mixture with water to remove the methyl alcohol, concentrating the ethylene dichloride solution, cooling it to approximately F. to F., removing a precipitated resinous red phenolic byproduct, cooling the ethylene dichloride solution to approximately 60 F. to crystallize nordihydroguaiaretic acid and separating the nordihydroguaiaretic acid crystals.

Description

Patented ay 27, 194? so res 2,421,109 METHOD or rnonncmc CRYSTALS or" NORDIHYDROGU ETIC ACID Joseph Adams, Chicago, Ill., assignor, by mesne assignments, to. Regents of the University of Minnesota, Minneapolis, Minn, a corporation of Minnesota No Drawing 7 Claims.
Application June 22, 1944, eriai No. 541,860
My invention has for its object the provision of an industrially practicable method of producing merchantable crystals of the anti-oxidant nordihydroguaiaretic acid.
An object and accomplishment of my invention is the production of original crystals of nordihydroguaiaretic acid that are pure and free from odoriferous contaminants, and thus admirably two selective solvents.
of the two selective solvents one is watermiscible; nordihydroguaiaretic acid is readily soluble in it but cannot be crystallized from it. The other solvent is water immiscible but miscible with the first solvent; nordihydroguaiaretic acid is only slightly soluble in it but can be crystallized out of it.
These and other objects, features and advantages of my invention presently will appear.
The material wherewith my method begins consists of some or all of the woody portions, leaves, stems, flowers, and buds of the so-called creosote bush (botanically named Larrea dwaricata) or, and preferably, an acidulatedalkali or alcoholic extraction thereof.
In the practice of my method a suitable quantity of the starting material is. digested with a water-miscible solvent (e. g., anhydrous methyl alcohol) that has been ascertained to be a very good solvent for nordihydroguaiaretic acid. When the soluble constituents of the starting material are in solution I dilute the water-miscible solvent with a very much larger (e. g., twenty-five times as large) quantity of a second or water-immiscible solvent (e. g., ethylene dichloride) that has been ascertained tobe one in which nordihydroguaiaretic acid is only slightly soluble, but which is miscible with the first or water-miscible solvent. The insoluble substances in the mixed solvents are now removed, preferably by filtering. to prevent any emulsificationof the solvents in the next step of the method. All of the foregoing preferably is accomplished under anhydrous conditions.
The mixed solvents are then subjected to vigorous agitation while there is being added thereto an amount of water substantially larger (e. g., four times as large) as the amount of the first or water-miscible solvent. By and as the result of this operation, which desirably is effected without permitting the temperature of the mixed liquids to fall substantially below 115 F., the first or water-miscible solvent is washed from the second or water-immiscible solvent, and such waterimmiscible solvent takes unto itself from said water-miscible solvent certain very finely dispersed particles including nordihydroguaiaretic acid--this transfer of solutes occurring because they are not soluble in the aqueous dilution of the water-miscible solvent. The agitation should be continued long enough to insure complete divorcement of the water-miscible solvent from the water-immiscible solvent. 7
After the period of agitation, the two resultant immiscible liquids are permitted to settleand are then separated. The one of such liquids which includes the second or water-immiscible solvent is then filtered to remove all foreign matter not in, solution.
Such liquid is then substantially concentrated, preferably by being heated in vacuo, in sumcient degree (e. g., nearly so that when it is subsequently subjected to controlled cooling and aided by agitation of theliquid, precipitates, first, a resinous red phenolic by-product and, second, a delayed crystal formation of nordihydroguaiaretic acid.
When such liquid has reached under controlled cooling a temperature 01' between 70 F. and 80 F., a resinous red phenolic by-product is precipitated and removed by filtration.
When by continuance of such controlled cool ing the liquid has attained a temperature of approximately F., it preferably is subjected to agitation which aiyls the development and precipitation of a, delayed crystal formation of nordihydroguaiaretic acid. These first crystals of nordihydroguaiaretic acid are removed from the liquid by filtration.
Next th liquid is again substantially concentrated (e. g., by 50%) preferably by being heated in vacuo, and is again subjected to controlled cooling to between F. and F., when an.- other precipitation of-the resinous redvphenolic by-product is removed by filtration. controlled cooling of the liquid to approximately 60 F., plus agitation, again causes the formation of a substantial quantity of crystals. These are removed irom the liquid by filtration and dried.
Further The liquid is next for a third time substantially concentrated (e. g., by 50%), preferably by being heated in vacuo, and is again subjected to controlled cooling down to between 70 F. and 80 F.', when another precipitation of the resinous red phenolic by-product is removed by filtration. Further=controlled cooling of the liquid to approximately 60 F.. plus agitation, enables me to.
realize a third substantial harvestof merchant- -able crystals of nordihydroguaiaretic acid.
In my method each harvest of crystalline antioxidantis preceded by precipitation and removal of the red phenolic by-product. This is of great importance; otherwise. the resultant occlusion of the red phenolic lay-product by the crystals would deprive the crystals of their essential purity.
While I prefer to employ methyl alcohol as my water-miscible solvent, I may use in lieu thereof various other water-miscible monohydroxy or polyhydroxy alcohols, such, for examples, as ethyl alcohol, isopropyl alcohol, propylene glycol and ethylene glycol; and while I prefer to employ ethylene dichloride as my watch-immiscible solvent, I may use in lieu thereof various chlorinated hydro-carbons such as chloroform, methylpracticing the invenrived from 100 lbs. of the young branches and leaves of the so-called creosote bush is digested with 3 gallons of hot 100% methyl alcohol. The resultant alcoholic sludge is then diluted with 75 gallons of ethylene dichloride. It is then heated to 130 F. and filtered to remove all insoluble fractions. The miscible liquids are then violently agitated while 12 gallons of water is added thereto to wash the methyl alcohol from the ethylene dichloride and to transfer from the methyl alcohol to the ethylene dichloride certain finely dispersed particles, including nordihydro uaiaretic acid, which have greatly reduced solubility' in a 20% solution of methyl alcohol in water. During the addition oi the water, the tem erature of the liquids is not permitted to fall below 115 F. The agitation is continued for 20 minutes, the two immiscible liquids resulting from the addition of water and the agitation .(i. e., (a) the aqueous alcohol solution, and (b) the ethylene dichloride and the solutes transferred to it) are permitted to settle for minutes and are then separated. The ethylene dimoved by filtration. The temperature of the ethylene dichloride is then lowered to 60 F., and a crystal formation 01' nordihydroguaiaretic acid is again developed by agitation. The crystals thus developed are removed by filtration. They are of commercial quality. The gallons of ethylene dichloride is next concentrated to 10 gallons, is again cooled down to 70 F., and then filtered to yield an additional quantity of the resinous red phenolic by-product. Its temperature is then againlowered to 60 a crystal formation of the anti-oxidant is again developed by agitation, and the resultant crystals, which also are of commercial quality, are removed by filtration. Further concentration of the ethylene dichloride followed by subsequent controlled temperature reductions and filtrations, will yield a relatively low crop of crystals of the anti-oxidant plus a relatively. large percentage of a gummy resinous product of a phenolic nature having much greater solubility in ethylene dichloride than any other previously precipitated resinous fraction. This gummy resinous residue may be collected until a. sufilcient accumulation warrants further dilution with ethylene dichloride followed by concentrations, controlled temperature reductions and filtrations, to reclaim in the form of merchantable crystals any nordihydroguaiaretic acid that may be present. 1
Reference is made to copending application of Ole Gisvold, Serial N0. 490,149, filed June 9, 1943. An acldulated alkali extraction of the creosote bush, prepared in accordance with the teachings of said Gisvold application, is a material suitable for treatment in accordance with my present invention.
Having thus described m invention, what I claim as new and desire to secure by Letters Patent of the United States is: l
1. The process of producing nordihydroguaiae retlc acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a first solvent selected from the group consisting of water miscible mono and polyhydric low aliphatic alcohols to produce a solution of nordihydroguaiaretic acid, adding to chloride fraction is then filtered. It is then concentrated, by being heated in vacuo, from 75 galions to 40 gallons. Controlled cooling of the concentrated solvent follows. when its temperature reaches 70 F., it is filtered to remove a resinous phenolic fraction. Further cooling of the concentrated solvent to F., plus constant agitation, results in a delayed crystal formation of nordihydroguaiaretic acid. The crystals from this first stage of crystallization are removed by filtration. They are of merchantahle quality. The ethylene dichloride is next further concentrated from 40. gallons to 20 gallons, and is again cooled down to F. when there is precipitated a red resinous phenolic by-product which is resaid solution a second solvent miscible with said first solvent, said second solvent being selected from the group consisting of monocyclic aromatic hydrocarbons and halogenated low aliphatic hydrocarbons,. washingthe mixture with water to remove the first solvent and crystallizlng nordihydroguaiaretic acid from the second solvent.
2. The process of producing nordihydroguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a first solvent selected from the group consisting of water miscible mono and polyhydrlc low aliphatic alcohols to produce a solution of nordihydroguaiaretic acid, adding to said solution-a much greater quantity of a second solvent miscible with said first solvent, said second solvent. being selected from the group consisting of monocyclic aromatic hydrocarbons. and halogenated low aliphatic hydrocarbons, introducing 3. The process of producing nordihydroguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a low aliphatic monohydric alcohol to produce a solution of nordihydroguaiaretic acid, adding to said solution-a halogenated low aliphatic hydrocarbon miscible with said alcohol, washing the mixture with water to remove the alcohol, and crystallizing the nordihydroguaiaretic acid from the halogenated hydrocarbon.
4. The process of producing nordihydroguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Larreu. divaricata containing nordihydroguaiaretic acid, with methyl alcohol to produce a solution of nordihydroguaiaretic acid, adding ethylene dichloride to said solution, washing the mixture with water to remove the methyl alcohol and crystallize nordihydroguaiaretic ,acid from the ethylene dichloride.
5. The process 'of producing nordihydroguaiaguaiaretic acid, with retic acidwhich comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydroguaiaretic acid, with a first solventselected from the group consisting of water miscible mono and polyhydric low aliphatic alcohols to produce a solution of nordihydroguaiaretic acid, adding to said solution a second solvent miscible with said first solvent, said second solvent being selected from the group consisting of monocyclic aromatic hydrocarbons and halogenated low aliphatic hydrocarbons, washing the mixture with water to remove the first solvent, concentrating the second solvent, permitting it to cool to approximately from 70 F. to 80 F., removing a precipitated resinous red phenolic by-product, cooling the second solvent further to approximately 60 F. to crystallize nordihydroguaiaretic acid and removing the nordihydroguaiaretic acid crystals.
6. The process of producing nordihydroguaia- 2 retic acid which comprises extracting an acidulated alkali extract of plant material of the species Larrea divaricata containing nordihydro methyl alcohol to produce a solution of nordihydroguaiaretic acid, adding ethylene dichloride to said solution, washing the mixture with water to remove the methyl alcohol, concentrating the ethylene dichloride solution, cooling it to approximately F. to F., removing a precipitated resinous red phenolic byproduct, cooling the ethylene dichloride solution to approximately 60 F. to crystallize nordihydroguaiaretic acid and separating the nordihydroguaiaretic acid crystals.
7. The process of producing nordihydroguaiaretic acid which comprises extracting an acidulated alkali extract of plant material of the species Lam-ea divaricata containing nordihydroguaiaretic acid, with methyl alcohol to produce a solution of nordihydroguaiaretic acid, adding to the resultant solution'ethylene dichloride in an amount approximately twenty-five times the amount of the methyl alcohol,adding to the resultant mixture water in an amount approximately four times the amount of alcohol, sepa-' REFERENCES CITED The following references are .of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,113,714 Taub Oct. 13, 1914 1,250,132 Blundell Dec. 18, 1917 2,096,922 Sankowsky Oct. 26, 1937 2,098,254 Mattill Nov. 9, 1937 2,318,748 Buxton'; May 11, 1943 1,758,616 McGavack May 13, 1930 2,209,019 Slagh July 23, 1940
US541660A 1944-06-22 1944-06-22 Method of producing crystals of nordihydroguaiaretic acid Expired - Lifetime US2421109A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US541660A US2421109A (en) 1944-06-22 1944-06-22 Method of producing crystals of nordihydroguaiaretic acid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US541660A US2421109A (en) 1944-06-22 1944-06-22 Method of producing crystals of nordihydroguaiaretic acid

Publications (1)

Publication Number Publication Date
US2421109A true US2421109A (en) 1947-05-27

Family

ID=24160530

Family Applications (1)

Application Number Title Priority Date Filing Date
US541660A Expired - Lifetime US2421109A (en) 1944-06-22 1944-06-22 Method of producing crystals of nordihydroguaiaretic acid

Country Status (1)

Country Link
US (1) US2421109A (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1113714A (en) * 1912-09-04 1914-10-13 Farbenfab Vorm Bayer F & Co Substance isolated from the apocynaceæ and process of producing the same.
US1250132A (en) * 1917-07-17 1917-12-18 Wm J Bryan Jr Art or process of making and extracting the medicinal properties of the larrea mexicana or hedionda.
US1758616A (en) * 1925-12-02 1930-05-13 Naugatuck Chem Co Method for recovering quebrachitol from rubber latex serum
US2096922A (en) * 1933-10-07 1937-10-26 Stanco Inc Method of preparing a mineral oil solution of derris
US2098254A (en) * 1936-08-28 1937-11-09 Lever Brothers Ltd Method and material for retarding oxidation and rancidity in food substances
US2209019A (en) * 1938-06-24 1940-07-23 Dow Chemical Co Crystallization of aspirin
US2318748A (en) * 1940-05-03 1943-05-11 Nat Oil Prod Co Refining and concentrating the unsaponifiable fraction of fats and oils

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1113714A (en) * 1912-09-04 1914-10-13 Farbenfab Vorm Bayer F & Co Substance isolated from the apocynaceæ and process of producing the same.
US1250132A (en) * 1917-07-17 1917-12-18 Wm J Bryan Jr Art or process of making and extracting the medicinal properties of the larrea mexicana or hedionda.
US1758616A (en) * 1925-12-02 1930-05-13 Naugatuck Chem Co Method for recovering quebrachitol from rubber latex serum
US2096922A (en) * 1933-10-07 1937-10-26 Stanco Inc Method of preparing a mineral oil solution of derris
US2098254A (en) * 1936-08-28 1937-11-09 Lever Brothers Ltd Method and material for retarding oxidation and rancidity in food substances
US2209019A (en) * 1938-06-24 1940-07-23 Dow Chemical Co Crystallization of aspirin
US2318748A (en) * 1940-05-03 1943-05-11 Nat Oil Prod Co Refining and concentrating the unsaponifiable fraction of fats and oils

Similar Documents

Publication Publication Date Title
US4116712A (en) Solvent refining of sugar
US5078920A (en) Process for separating mixed fatty acids from deodorizer distillate using urea
US2866797A (en) Improved process of isolating sterols
US2948716A (en) Purification of sugar esters
US3253023A (en) Recovery of 3-(3, 4-dihydroxyphenyl)-l-alanine from velvet beans
US2421109A (en) Method of producing crystals of nordihydroguaiaretic acid
US2078963A (en) Process for refining crude naphthalene
US2348215A (en) Process for the manufacture of hesperidin
US2508545A (en) Process of recovering caffein
US2790837A (en) Continuous production of trimethylolethane
US2371467A (en) Preparation of cholesterol
US2610195A (en) Recovery of unsaponifiables from concentrates containing the same
US2938028A (en) Purifying and dewaxing citrus oils
US2648687A (en) Process of preparing cholesterol
US1758616A (en) Method for recovering quebrachitol from rubber latex serum
US2574165A (en) Process for the manufacture of the gamma isomer of hexachlorocyclohexane
JPH04306296A (en) Production of liquid fatty acid and solid fatty acid
US2744919A (en) Producing pure dihydroquercetin
US2355661A (en) Extraction of sterols
US2010384A (en) Process for the separation of isomeric pentanones
US2054271A (en) Production of crystallized hormone esters
USRE25135E (en) From about
US1940146A (en) Process of purifying phenolphthalein
US2451116A (en) Method of recovering albumin adhering to egg shells
US1953607A (en) Method of recovering carotene from green leafy plant materials