US2541127A

US2541127A - Process for producing dehydroperillic acid

Info

Publication number: US2541127A
Application number: US33638A
Authority: US
Inventors: William G Van Beckum
Original assignee: Weyerhaeuser Timber Co
Current assignee: Weyerhaeuser Timber Co
Priority date: 1948-06-17
Filing date: 1948-06-17
Publication date: 1951-02-13
Anticipated expiration: 1968-02-13

Description

Feb. 13, 1951 w. G, VAN BEcKUM PROCESS FOR PRoDucING DEHYDRGPERILLIC ACID Filed June 17f 1948 MMl m Il E. tEu

mmhl

INVENTOR. W/LL/AM G Vd/V BEC/(UM ATTORNE YS Patented Feb. 13, 1951 PROCESS FOR PRODUCIN G DEHYDRO- PERILLIC ACID William G. Van Beckum, Longview, Wash., as-

signor to Weyerhaeuser Timber Company, Longview, Wash., a corporation of Washington Application .lune 17, 1948, Serial No. 33,638

(Cl. 26th-,124)

6 Claims.

`rIhis invention relates to a process for the production of an organic acid, and more particularly pertains to a process for the production from lignocellulose materials of an organic acid heretofore identified and known as dehydroperillic acid. The `process of the invention is particularly applicable to the production of the said acid as a by-product of a commercially feasible process for the production of lienin from aqueous alkaline extracts resulting from the treatment of fiber derived from certain species of woods with a dilute aqueous solution of an alkali metal hydroxide, This application is a continuation-inpart ofabandoned application Serial No. 602,916, filed JulytZ, 1945.

yThe properties of the acidic compound which isa product of the process of the invention indicate that it may be an analogue of perillic acid, diferingftherefrom in that it contains one additional double bond in its molecular structure. It has, therefore, been tentatively named dehydroperillic acid (cf. Journal of the American ChemicalrSociety, v. 55:3813-9 (1933)). The relationship between the two compounds is clearly evident from the following structural formulas:

Formula I Coon t 112C/ C\ C@ CH2 lFertilia acid `Formula, II

,Icoon When wood is used as a source material for the production of dehydroperillic acid in accordance with the herein described process, it is preferablyiirst reduced to Afibrous form by mechanical or other methods which do not subject the wood to the action of added chemicals other than Water. This reduction is carried to the point Where itresults in the conversion of -the wood substance to bers `physically consistingsubstantially of ultimate fibers and opened-up bundles of ultimate bers and constitutionally consisting primarily of cellulose, lignin, and polysaccharides-other-than-cellulose, `herein frequentlyreferredto merely as .polysacoharides, these three constituents being present in mutual ratios in the range of contents falling `between that characterizingthe raw Wood from which the fiber is derived and that characterizing .the water-insoluble content .of the raw .Woodfrorn which the fiber is derived. .Fiber containing ce1- lulose, lignin, and polysaccharides-other-thancellulose in the range characterizing the Waterinsoluble content ci .the raw `vvood `from which the ber is .derived is exemplied by raw Wood ber which has been so treated with water as to extract the water-soluble constituents and leave as' a fibrous `residue the Water-insoluble content of the wood. The production of such ber from Woods such as western larch isof `particular interest, since these `woods Acontain high percentages of Water extractablesubstances.. as. about, 23% in the case of western larch. It may, therefore, be commercially desirable in the case of these woods to extract them with Water in order to isolate vas commercial products the water-soluble fraction of the wood substance. Aiiber residue is thus obtained which maybe employed to advantage as a raw material for the fractionation process` of the instant invention.

The wood fibers to which the process or" the invention may satisfactorily be applied may be produced, for example, bythe method described in United States Letters Patent No.71,913,607 to McMillan. This patent describes a mechanical debering process entirely free from chemical action, which comprises combing out substantially ultimate bers from Wood by contacting logs of wood With high speed rotary radial elements such as pointed pins projecting` from an axle, like bristles. Fiber produced .by this process is herein referred to as McMillan ber, or pin fiber.

Wood ber suitable for use in the process of the present invention may also be prepared by themethod described in the United States Letters Patent No. 2,668,892 to Asplund. In this method Wood substance is debered by mechanically reducing the Wood While simultaneously applying sufficient steam `pressure to soften the lignin in the middle 1amel1a',lthus permitting easy debrationof the softened wood. The ber re-` 3 sulting from this practice in ecient operation of the commercial Asplund machine is termed herein normal Asplund fiber, or normal deiibrator ber. wood while exposing it for about one minute to high pressure steam at a temperature sun'cient to eiect the desired softening.

Other processes may be employed for reducing wood substance to said ultimate nbersor openedup bundle form. The Wood substance may be affected by steam at any time or times before, during or after such deilbration. Action by steam should be such as to avoid any substantial gasication of the Wood substance which thus leads to lossor decomposition of Wood substance, usually with the formation oi' furiural, as well as to a1- tered proportions or" the three primary constituents, and unduly altered forms of said constituents. The bers resulting from processes involving both debering and steaming, which includes those resulting from the Asplund process, differ from the raW Wood in that their Water-soluble content has been to a greater or lesser degree increased by the action of the steam. In the case of normal Asplund aspen bers made in about one minute at about 128 pounds Ysteam pressure, the increase in Water-soluble content is 4% to 6%.

Other methods for producing fibers from Wood substance may also be used, provided said methods do not subject the wood to the action of added chemical agents other than liquid Water or steam.

It has been discovered that dehydroperillic acid may be obtained by subjecting lignocellulose materials which contain it 'to the action of a dilute aqueous solution of a basic-acting compound of an alkali metal, separating the treated material from the resulting solution, and isolating from the said resulting solution its content of dehydroperillic acid.

More specifically stated,.dehydroperillic acid is obtained from lignocellulose materials, e.g. VWood ber, in accordance with the process of the present invention, by treating such materials with an aqueous alkaline reagent preferably comprising a Weak aqueous solution of an alkali metal hydrox.

ide, e. g. sodium hydroxide, at an elevated temperature for a time sufficient substantially to exhaust the extracting action of the alkali, thereby forming a solution comprising dehydroperillic acid, polysaccharides-other-than-cellulose, and lignin, and leaving a brous residue, separating the said solution from the said residue, and concentrating and acidiiying the said solution in order to separate therefrom its dehydroperillic content.

. A specific embodiment of the invention for obtaining dehydroperillic acid from lignocellulose material is illustrated in the drawing. In accordance with the procedure therein outlined, lignocellulose material, e. g. the liber ofv western red cedar, indicated at 7, containing substantially all of the Water-insoluble content of the wood from which the iiber is derived, and prepared by the heerinabove referred to Asplund, McMillan or other processes, and physically consisting substantially of ultimate bers and opened-up bundles of ultimate bers and constitutionally consisting primarily of cellulose, lignin, and polyl saccharides-other-than-cellulose, said three con- Y treated at 8 with an'alkaline reacting` compound of. alkali-metal. The alkaline reagent employed is It is prepared, for example, by reducing.

typically exemplied by sodium hydroxide, e. g; a

-1/4 normal solution of alkali-metal hydroxide, in

a total amount with respect to ber sufficient to maintain an extracting alkalinity during the operation. This treatment is preferably carried out at atmospheric pressure and at about the boiling point of the said solution. The time of treatment is Variable depending upon the type of Wood being treated and the' other conditions of the treatment,

but, in general, may be up to about two hours, or Y such time as shows the extraction to be substantially complete.r This treatment extracts from the Wood substance the dehydroperillic acid as Well as a substantial proportion of the lignin and polysaccharides-other-than-cellulose content and leaves a brous residue. The reactedY mass is extracted at step IG to separate the soluble matterfrom the thus, treated fiber. Y

Step e may be practiced by a batchwise procedure or by a counter-current or recycling pro-- cedure as hereinafter more `fully discussed. Water is usually employed as the solvent in step IS, but the water may also be admixed with other materials in order to contribute specific properties to the solvent or for specic purposes. Water alone, or With such othergmaterials admixed therein, is herein referredto as an aqueous Vsolvent. Steps 3 and iil may be eiiiciently combined when an aqueous solution of sodium hydroxideY `or solution I5, arbitrarily herein designated Extract I, which contains the dehydroperillic acid,

lignin and the other organic materials including the polysaccharides-other-than-cellulose.

After separation of the said residue I3 from the lextract 25, the said-extract is treated for isolation of its dehydroperillic acid content. It is rst neutralized at step IS, preferably by adding sulfurie acid, thereby reducing the pH from an original value of about 10 to one of about 7. The

. solution as thus acidified is then conditioned for precipitation at step I8. .This conditioning may take one of tvvo forms, or a combination of both by either the removal of water of solution, step 2li, or by the addition-of inorganic salts, step 22. Both treatments have in common the fact that they result in the concentration of the solution to a point at which completion of the lignin precipitation is eiected. The precipitated lignin is then iiltered at step 24 and recovered at 25 as product lignin l-a.

It is desired at this point to elaborate on step it of conditioning the solution for precipitation of thelignin, especially since this same step is generally applicable at other steps in the process, or in other sequences, to the separation of theV other lignin products at other pI-I ranges. Y While,

some precipitation of lignin may occur by virtue of establishment of the pH range for separationi of the lignin product concerned, the separation of the lignin in this manner is not sharp, and it is advisable to condition the solution inorderto.

eiect the complete precipitation of all the lignin which Will separate at the particular pI-I range.

tinlied to a point Where thelignin content is precipitated in substantial amount. The solution is preferably maintained neutr-al during the concentration step by the addition of acid as necessary. I-t will be obvious that the need for concentration by removal of water will depend upon the usage ofalkali and-the concentration of the alkali in the solution i5. The more the salt content formed by the interaction between the alkali and the acid, the less will be the extent to which the removal of water needs to be continued. t will be further appreciated in this connection that steps iii and i8 are more or less interdependent and that either'step may be performed first; that is, either the removal of water or the addition of the salt may precede acidification. It is generally more advantageous, however, for step I8 to follow step I6, because, in this manner, full advantage can be taken of the salts formed by the neutralization of the alkali present.

When the conditioning of the solution for precipitation is to be accomplished by the addition of inorganic salts as at 22, sodium acid sulfate is preferably used, and is added until the solution is near saturation with respect to this compound. At this point, precipitation of lignin 1-a can be expected to be substantially complete. The neutral, concentrated solution containing undissolved lignin, preferably at room temperature, is filtered at 2d, thereby separating lignin l-a, designated at 25, in the solid form.

The filtrate 26, which contains the dehydroperillic acid in salt" form together with the polysaccharides-other-than-cellulose and additional lignin products, is next acidified to a pH of about 5 at step 2l'. This causes the precipitation of the dehydroperillic acid together with an additional lignin product. The resulting mixture is then warmed to a temperature of about 65 C. at step 28 in order to ccagulate the lignin product and effect its separation from the dehydroperillic acid. Upon cooling, the coagulated lignin product is to be found in large part settled out on the bottom of the containing vessel, while the supernatant liquid contains suspended crystals of dehydroperillic acid together with a line suspension of lignin product particles. Since the particle size of the dehydroperillic acid crystals is substantially greater than that of the suspended lignin product particles, it is possible to eifect the separation thereof, as by decanting the supernatant liquor fromthe coagulated lignin product remaining in the vessel, the said supernatant liquor being passed through a ltering means whereof the mesh size is such as to permit passage of the iine particles of suspendedV lignin product, but to retain the larger dehydroperillic acid crystals. This is represented at step29. This results' in the formation of a ltrate 3l, which contains lignin products in aqueous solution and in suspension, together with polysaccharides-other-than-cellulose in aqueous solution, and, as a solid product inV cake form, the crude dehydroperillic acid 32. This acid may be refined, as by washing with cold Water, at step 33 to give a purified dehydroperillic acid product 34, while the filtrate 3| may be processed to isolate valuable polysaccharidesother-than-cellulose and lignin products therefrom.

It will be apparent that the operating conditions a`s described in the preferred embodiment may be varied as desirable or necessary when processing different types of lignocellulose materials or employing a range 'of reagent concentrations. For example, various alkaline' materials may be employedin the treating step' 8; Suitable" alkaline Vmaterials include in general the hydroxides of the alkali metals as well as those alkali metal compounds which, being salts of strong bases and weak acids, undergo hydrolysis in aqueous medium to form the alkali metal hydroxides, or their equivalent in alkali metal ions and hydroxyl ions. Such compounds are, therefore, the basic-acting compounds of the .alkali metals, i. e. of lithium, sodium, potassium, rubidium, and caesium. The hydroxides of this group of metals, especially sodium hydroxide, are preferred reagents for effecting the herein described extraction, although the carbonates, e. g. sodium carbonate, may also be used.

Similarly, the operating conditions of the extraction step, wherein the lignocellulose material is treated with a dilute aqueous solution of alkali, may be varied within limits to suit the particular lignocellulose material being treated. It is the teaching of the invention, however, and often critical to its success in practice, to use and maintain operating conditions and reagents of such a mild character as to effect the fractionation of the lignocellulose materials without causing substantial or drastic changes in the composition of the constituents thereof. Thus, it is preferred to use a relatively Weak Vsolution of alkali, i. e., a solution which contains suiicient alkali to be about 1/4 normal with respect thereto. A preferred solution for effecting the extraction is a 0.6% solution of sodium hydroxide.

Usages of alkali-largely in excess of those necessary to obtain the desired fractionation are also avoided. The total amount of alkali metal hydroxide used is usually based upon the weight of fiber treated. Thus, for example, a usage of 15% sodium hydroxide signies that l5 parts by weight of sodium hydroxide is used to extract parts of dry ber.

Where a mixing procedure is employed in the extraction with alkali metal hydroxide, the consistenc'y of the reaction mixture (i. e. the Weight of fiber per 100 parts by weight of solution) is maintained at a level such as to afford ease of manipulation and thoroughness of treatment.

The optimum consistency is obviously dependent upon many factors, principally upon the method of handling the ber mixture. Thus, varying Vconsistencies may be used, depending upon whether the ber is treated batchwise, or continuously, as in counter-current operation.

It will be apparent that concentration, usage and consistency are interrelated factors and that variations in one will aifect the others. Thus,

when the concentration and usage are varied,

the consistency also changes. Various combinations of these variables are possible, the practical limiting factors being, as disclosed above, the desirability of keeping the operating conditions relatively mild, and also of providing consistencies such as to favor ease of handling, drying, processing and relatively complete separation of extract from treated material. A representative combination of these variables suitable for use in extracting many Woods in fibrous form comprises the use of an aqueous sodium hydroxide solution having a concentration of 0.6% by weight sodium hydroxide in an amount equal to 15% by weight of the liber treated, whereupon the consistency of the mixture will be about 4%.

As stated hereinabove, the alkaline extraction is carried out at a temperature which is preferably about the boiling temperature of the mix- 7'5 tu're at normal atmospheric pressure. In ordinary operation, it is usually preferred, when batchwise extraction is being practiced, to recycle thealkaline solution used in the extraction. In this manner the dehydroperillic acid concentration isV built up in the alkaline solution to a point where the said solution becomes an increasingly valuable source thereof. Since some of the alkali is consumed by reaction with the wood substance during the extraction process, it is desirable to add a further quantity of alkali before treating fresh wood fiber. in the case of woods such as Western red cedar extracted at 4% consistency with a 0.6% solution of caustic soda, about 60% replacement of the original caustic alkali usage after each extraction is Sunicient to fortify the solution to the desired degree, e. to a concentration of about 6.6% in the case of caustic soda. Although the number of times an alkaline solution which Yhas been thus fortied may be used for the'extraction of raw wood is variable depending largely uponY the nature of the woodfithas been observed that extracting eight times in the above described manner and fortifying the resulting extract with additional alkali before each extraction results in the production of an alkaline extract rich in dehydroperillic acid, lignins and polysaccharides-other-thanfcellulose and, at the same time, leaves a fiber residue of useful composition and properties.

Recycling, or its equivalent operation, may be profitably practiced until the contribution of dehydroperillic acid of each new batch of fiber equals the amount of dehydroperillic acid retained by the iibers upon separating the bers and the extract. Obviously, this involves many factors including the amount of dehydroperillic acid contributed by each successive batch of fiber as well as the emciency of the mechanical step of eiecting the separation.

Similarly, the operating procedures hereinabove outlined for the processing of the aqueous alkaline extract resulting from the treatment of the lignocellulose material with a dilute aqueous solution of an alkali-metal hydroxide may be varied within'limits. It is a primary objective of the procedure, however, to provide conditions which will achieve the difficult function of separating the desired dehydroperillic acid product in a relatively pure form, uncontaminated by substantial quantities of the other constituents of the complex extract from which it .is isolated, ie. uncontaminated by polysaccharides-other-thancellulose, mineral salts such as sodium sulfate, and, particularly, lignin. Thus, although it may be possible in some cases to separate the dehydroperillic acid from the extract without the prior separation of lignin l-c.' as by acidification of the said extract directly to a ph. of about 5, followed byA concentration the desired degree and separation of the dehydroperillic acid from the precipitated lignin, it has been found that a more sharply defined separation of lignin from dehydroperillic acid and a purer product are obtained when the extract is freed from some of the lignin products, i. e., lignin lea, before the separation of the dehydroperillicacid is effected.- Various acids may be used at step l l' for neutraliaing the dehydroperillic acid-containing extract. Any of the common mineral acidssuch as sulfuric acid, phosphoric acid, or hydrochloric acid, as well as some ofthe organic acids, e. g. acetic acid, are suitable for this purpose. Sulfuric acid is a preferred member of this group.

The amount of acid used is likewise variable, andY depends largely upon the alkalinity of the extract. In general, enough acid is employed to result in the formation of asubstantially neutral solution, i. e. one having a pH of about '7.

As stated, the neutralized extract is preferably concentrated to a point at which lignin l-a is insoluble, but at which the dehydroperillic acid, polysaccharides-other-than-cellulose, and inorganic salt content of the extract, principally sodium sulfate whencaustic soda and sulfuric acid are used in the extraction and acidication steps, and some other lignin products are substantially soluble. There is thus removed from the extract a substantial amount of lignin products of relatively low acidity, thereby simplifyingV the separation of the dehydroperillic acid at a later stage. Although the point at which this desideratum is attained varies with the relative proportions of solvent and solutes and with other factors, when the proportions and operating con- Y drawing, wherein theaqueous solution remaining after separation of lignin l-a, is Yaciduded to a pI-l oi about 5, is likewise subject to variation within limits. It is the general'objective of this step to acidify the solution to a point at which the dehydroperillic acid, up to this stage of the procedure in the form of a water-soluble salt, is converted to the free acid, which is insoluble in cold water, without effecting the precipitation of lignin products in amount suiiicient to make the separation of the dehydroperillic acid in a relatively pure state diihcult, if not impossible. It has been discovered thatacidication to a pH of between about and 6 usually accomplishes this purpose, a pH of about 5 being a preferred value. The acidication may be effected using any suitable acid of suiiicient strength to reduce the pH of the solution to the desired level. Sulfuric acid is a preferred reagent for this use.

Step 28 has for its general object the coagulation of the lignin products which, together with dehydroperillic acid, almost invariably precipitates upon acidication of the solution to pH 5. The desired coagulation may be secured by warming the suspension, for example to from about 55 C. to about 75 C., preferably about 65 C. This step causes a large part'of the lignin product to aggregate and settle to the bottom of the containing vessel, thus leaving a supernatant liquid containing as suspended crystals the desired dehydroperillic acid, together with some finely dispersed lignin product, and dissolved inorganic salts and polysaccharides-other-thancellulose. Upon cooling, a further quantity of dehydroperillic acid separates. During the process of cooling the dehydroperillc acid forms crystals which are considerably larger in size than are the suspended lignin product particles. They may, therefore, be separated therefrom by pouring the supernatant liquid through any suit` able typeof lterhaving a mesh size such that amara? 9 the lignin product; particles pass therethrough but the dehydroperillic acid crystals are retained upon the lter. The desiredl separation is thus effected.

Purification of the crude dehydroperillic acid, obtained as above, may be accomplished, as is indicated at step 33 in theV drawing, by washing one or more times with a solvent comprising cold water. Alternatively, the purication may be effected by dissolving the dehydroperillic acid product in a suitable solvent and recrystalliz- `ing it therefrom. Alternatively, also, it may be dissolved in an aqueous solution of a suitable alkali, such as sodium hydroxide, thereby forming an aqueous alkaline solution of the dehydroperillic` acid salt', asl sodium dehydroperillate, which may be reprecipitated as the free acid in aA relatively pure state by acidification of the solution to a pH of about 5. Sublimation aiords another method of purication.

It is to be understood that the term lignin product is used herein to designate lignin products obtained byl chemical treatment of lignooellu'lose materials, although it is recognized that the lignin thus produced may have been altered in form or properties to a greater or lesser degree by reaction with the chemicals with which it has been treated.

The process of the invention is illustrated by the following example, wherein the parts are expressed as parts by weight:

Example parts by weight of ber per 100 parts of solution.

The extraction was effected at the boiling temperatures of the solution at about normal atmospheric pressure forV a duration of one hour. The ber was then separated from the sodium hydroxide solution and Washed with water for sub- I sequent uses. The alkaline extract was fortied by the addition of caustic soda in an amount sunicient to build up the sodium hydroxide concentration to a level substantially that of the original solution. This required replacement of about 60% of the original sodium hydroxide. The fortified solution was then employed in the extraction of a further quantity of raw wood fiber. A total of eight extractions of raw wood fiber was carried out in this manner, replenishing the concentration of sodium hydroxide in the extracting solution after each extraction. This resulted in the production of an alkaline extract containing dehydroperillic acid and other materials removed from the wood substance.

Y This alkaline extract, which had a pI-I of about 10.y was then processed for the recovery of its dehydroperillic acid content by neutralizing with sulfuric acid and concentrating by evaporation while adding further sulfuric acid` as necessary i to maintain the solution neutral. The solution was thus concentrated to` about 12% of its original volume. lIt was then cooled and filtered. This resulted in the separation of lignin products 1-a.

cri

The filtrate, resulting from the separation of lignin l-a was acidied to a pH of 5, thereby precipitating dehydroperillic` acid, together with a quantity of another nely divided lignin product. This mixture was heated to a temperature of C., andA then allowed to cool slowly. This caused most of the lignin product to coagulate and settle to the bottom of the containing vessel within a few hours. After this treatment, the liquid above the coagulated lignin product contained a fine dispersion of lignin product particles together with relatively large crystals of dehydroperillic acid. It was decanted through Va coarse filter, thereby effecting the separation of the dehydroperillic acid. Purification of the latter was effected by merely washing on the filter with cold water.

The product as thus produced was a white, crystalline solid having a melting point of about 88 C. Color tests with ferrie chloride reagent were negative, indicating that the product was not a phenol. The presence of at least one carboxyl group was indicated by the fact that the product Was soluble in sodium bicarbonate to give a solution from which it could be reprecipitated by acidification. No methoxyl groups were present. The neutral equivalent was determined to be 159. This value, coupled with the empirical formula (CsHcO as determined from carbon-hydrogen analysis data, indicates the molecular formula to be C1QH12O2. This corresponds to the formula for dehydroperillic acid as given above.

Two derivatives of the above described acid product were prepared. The methyl ester melted at 34 C. to 350 C. and boiled at 104 C. to 106 C.

The anilide, prepared by reaction of the acid or of its acyl derivatives with aniline, Was a crystalline compound melting at 96 C.

It is apparent that the process of the present invention has manifold advantages. In. the rst place, it accomplishes the isolation of a pure, well defined organic chemical compound from Wood substance. It represents for the iirst time a commercial process for the production of dehydroperillic acid. It makes available at relatively 10W cost a new and useful chemical product, which has many potential applications per se, or as a starting material for the processes of the synthetic chemical industry. Finally and broadly, it represents a successful effort to obtain a useful chemical lay-product from a mild-controllable procedure for the fractionation of wood substance.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. The process for treating lignocellulose material for the recovery of dehydroperillic acid and lignin precincts, comprising treating a lignocellulosic source material for said acid and liguin with an aqueous solution of a basic-acting compound of an alkali metal at a temperature of from about normal room temperature to about the boiling point of said solution at atmospheric pressure and-in concentration sufficient to provide not substantially more than about 15 parts by weight ci said alkali metal compound per 100 parts of dry lignooellulose material for forming an extracted mass of said material and an' adueous alkaline extract containing dehydroperillic acid and lignin product, separating the said mass from the said extract, `substantially neutralizing said alkaline extract and conditioning it by establishing a` salt concentration sufficient to eiect "precipitation of a substantial amount of lignin products, separating the precipitated lignin products thereby leaving a residual extract, acidifying the residual extract to a pl-l value of between i kand 6 for precipitating dehydroperillic acid and lignin, and separating the thus precipitated dehydroperillic acid from the co-precipitated lignin and acidiiied lignin-containing extract.

2. The process for treating lignocellulose material for the recovery of dehydroperillic acid and lignin products, comprising treating a source material for said acid and lignin with an aqueous solution Vof a basic-acting compound of an alkali metal at a temperature of from about normal room temperature to the boiling point of said solution at atmospheric pressure and in concentration `sufficient to provide not substantially more than about V15 parts of said alkali compound per 100 parts of dry lignocellulose material for a time period Ysufiicient substantially to exhaust the action of the solution for forming an extracted mass of said material and an aqueous alkaline extract containing dehydroperillic acid and lignin product, separating the said mass from the said extract, substantially neutralizing said alkaline extract and conditioning iteby establishing a salt concentration suiicient to effect precipitation oi a substantial amount of lignin products, separating the precipitatedilignin products thereby .leaving a'residual neutral extract, acidiiying the residual extract to a pH value of between 4 and 6 for precipitating dehydroperillic acid and lignin, Vand separating the precipitated dehydroperillic acid from any cti-precipitated lignin and' Ylignin products, comprising treating a source material Yfor said acid and lignin with an aqueous solution of Va hydroxide of an alkali metal at a temperature of from about normal room temperature to about the boiling point of said solution at Y atmospheric pressure and in concentration suf- Ycient to provide not substantially more than about l5 parts of said alkali compound per l0() parts of dry lignocellulose material for forming an extracted mass of said material and anadueous alkaline extract containing dehydroperillic -ltween-Ll and 6 for precipitating dehydroperillic acid, and separating the thus precipitated Vdehydroperillic acid from any (zo-precipitated lignin Vand the acidiiied lignin-containing extract.

, 4. The process for treating lignocellulose material for the recovery of dehydroperillic acid and taining dehydroperillic acid and lignin products, separating the said extract from the extracted material, neutralizing the said extract and conditioning it by establishing a salt concentration sufiicient to effect the precipitation of a substantial amount of Vlignin products, separating the precipitated lignin products from the residual neutrai solution, acidiiyiing the residual neutral solution to a pl-I of between 4 and 6 for precipitating dehydroperillic acid, and separating the precipitated dehydroperillic acid from any co-precipitated lignin products and from the residual acidified solution. 5. The process for treating lignocellulose material for the recovery of dehydroperillic acid and lignin products, comprising treating a source Inaterial for said acidrand lignin products VWith an aqueous solution of aY basic-acting compound of an alkali metal at a temperature of'from about, normal room temperature to the boiling point oi'V said solution at atmospheric pressure and in concentrationsufcient to provide not substantially conditioning it by establishing aV salt concentra,-Y

tion sufcient to eiect the precipitation of a substantial amount of lignin products, separating the precipitated lignin products from the residual neutral solution, acidiiying the residual neutral solution to a pl-I ot-between 4 and 6 for'precipitating additional nely divided lignin Yproduct particles and relatively large crystals of, dehydroperillic acid, Vand filtering the resulting aqueous suspension through a filtering means having a rnesh size such as to permit the passage of the aqueous medium and 'of the finely divided lignin product particles but to retain the dehydroperillic acid crystals.

6'. Aprocess for the production'roi dehydroperillic acid and lignin products from Wood, which comprises treating comminuted Woodwhich isY a source material for said acid and-lignin with an aqueous solution of an alkali metal hydroxide at a temperature of from about normal room teinperature to the boiling point of said solution at i atmospheric' pressure and in concentration sui-f ncient to provide not substantially more than about l5 parts of said alkali metal hydroxide per Y 100 partsof dry wood for a time period suicient substantially to Yexhaust the action of the said: solution for forming an extracted'Inassrroi"Woodl and an Yaqueous alkaline extract containing de-V Y hydroperillic acid and ligninv products, separating lignin products, comprising treating a source material for'said acid and lignin products with an Y aqueous solution of an alkalimetal carbonate at Y a temperature of from about normalroom telnperature to the boiling point oi said solution at atmospheric, pressure and in concentration suivlcient substantially to exhaust'the action of said solution for forming an extracted mass of said Vmaterial and an aqueous alkalineV extract conthe said extract from the extracted liber, substan- Y cipitated ligninr products from the vSaid solution,

acidiiying said neutral solution to a pH value of y between about 4 and 6, and'separating the' thus precipitated dehydroperillic acid from .any cocontaining solution.

WILLIAM G. VAN BECKUM.

' No references cited

Claims

6. A PROCESS FOR THE PRODUCTION OF DEHYDROPERILLIC ACID AND LIGNIN PRODUCTS FROM WOOD, WHICH COMPRISES TREATING COMMINUTED WOOD WHICH IS A SOURCE MATERIAL FOR SAID ACID AND LIGNIN WITH AN AQUEOUS SOLUTION OF AN ALKALI METAL HYDROXIDE AT A TEMPERATURE OF FROM ABOUT NORMAL ROOM TEMPERATURE TO THE BOILING POINT OF SAID SOLUTION AT ATMOSPHERIC PRESSURE AND IN CONCENTRATION SUFFICIENT TO PROVIDE NOT SUBSTANTIALLY MORE THAN ABOUT 15 PARTS OF SAID ALKALI METAL HYDROXIDE PER 100 PARTS OF DRY WOOD FOR A TIME PERIOD SUFFICIENT SUBSTANTIALLY TO EXHAUST THE ACTION OF THE SAID SOLUTION FOR FORMING AN EXTRACTED MASS OF WOOD AND AN AQUEOUS ALKALINE EXTRACT CONTAINING DE-