USRE22393E - Process of producing wood - Google Patents

Description

Reiasued Nov. 23, 19 43 UNITED STATE 1 Georgia ,No Drawing. original No. animated Y I 28, 1942, Serial No. 345,446, July 13,1940. Ap-

plication i'or reissue April- Z6, 1943, .SerialNor 12 Claims. (01. ce-53),

The invention relates to the production of wood I preservatives by-treatment of tars, such as coal tar, gas house tar, low temperature tar, water gas-tar, blastfurnace tar,-lignite tar,- wood tar,

pine tar and oils, rosin, rosin oil, fractions and residues derived therefrom, including pitches,

with hydrogen; high boiling aromatic extracts frompetroleum and tars resulting from polymerization of petroleum or fractions thereof.

It is an object of the present invention to-provide an improvements upon my Patents No: 2,082,885, dated June 2, 1937, and No 2,125,918, dated August 9, 1938. In the former patents referred to there'is'described a process for producing a wood preservative of the nature of a synthetic creosote by--the treatment of pitches of various character 'with hydrogen, using a stated upper limit of' substantially 200 atmospheres; pressure. Further experiment with the process oisaid former patents has shown 'an advantage of greatly {increased pressures above those mentionsd in said ipatent. It is therefore an object of the present invention to improve upon the process 'ofsaid former patents by raising the pressures to any point needed to avoid difliculties found with the process as described in said former patents. An object of the present invention is the thermal protection and conservation of those fractions responsible for toxicity induction.

As is'well known, the induction of toxicity in amixture of aromatic tar fractions, as for instance a mixture of coal tar fractions, is only attained if during hydrogen action the aromatic nuclei of the starting material is protected against excessive rupture and destruction. Rupture and-destruction of the aromatic nuclei results in the production of substantially nontoxic materials or materials that are not toxic in the accepted sense. Accordingly, the instant process of toxicity induction may'be explained as being predicated on, among other things, protecting the aromatic nuclei during hydrogen action. As. is well known in the art, protection of the aromatic nuclei against rupture and destruction is accomplished by the proper coordination ofthe time, temperature and pressure. v a It is found that working with a coal tarpitch boiling substantially 12% at 355 C. when the said pitch was treated with hydrogen at a pressureof 200 atmospheres and a temperature oi 385- C. for four hours without a'catalyst, there was induced about 15 per cent of newly formed fractions falling within the specifications of the desired creosote. It is of great 'im'portance to increase the percentageof the formation of desired oil per. cycle. .To this end it was attempted to secure an increased 'conversion'by increasing the temperature, whereupon it was'ffound that the reverse was the fact, for thereason thatthe higher, temperature caused a portion of the original pitchto form coke an'dan actually reduced percentage of synthetic creosote resultedg After a great amount of research and experimentatioirit was round that the desired result could be had by utilizing the higher temperatures in combination with; the use of sufficiently high pressure above the 200 ;-atmospheres heretofore used, which increased pressuremayneed beas high as, or higher, than'LOOO atmospheres. To

in its normal condition has about as much carbon residuezas is possible of use-.with the temperatures and pressures mentioned in my former patents, under 'the, (influence of the increased temperatures is partially vaporized and is acted upon in both the liquidandthe vapor phase, but the vaporization of ap'ortioh of the molten pitch results in increasing the efiective carbon residue of pitch remaining 'liquidin the oven, thus resulting in an excessive formation of coke whichv clogs the retort and blocks further operation. 1' a i.

Tars apparently react-- the same as pitches, that is to say, tars when under conditions 01' the process, wherein temperature and pressure fail to be coordinated as above taught, result in the partial vaporization of 's'aid tars to the end that in the unvaporized portion thevcarbon content has been so increased that the thermal sensitivity results in coking.

However, utilizing pressures considerably in excess of 200 atmospheres even as high as 1,000 atmospheres or higher, when the treatment is carried on at a temperature well-above 400 C. no such coking takes place for the reason, as is believed, that the action evenunder the increased temperature is still carried outin; the liquid phase, or at least predominantly so. I

In the case of certain pitches it has been found the pressures of from 225 ,to 500 atmospheres sutfice to 'eliminat'ecoking conditions when using that W111 sutstanmny raise the carbon content in the pitch rernaining liquid, to a detrimental point in the oven or bomb will be sufiicient to plfma io io c k wh h mnsrature even fabdye MOP Q. is not cause thereferr'edto amount of vaporization at the pressure used.- Thus, the present invention -prvides a process for so co-ordinating temperature and pressure, said temperature being,:s',plu-;taz;-,-3 .tially 400 C. or above, and said pressurefilibdwe pr ss e s ms entotect those 200 atmospheres, that the to conserve and thermally pr 7 responsible for toxicity induction. 1;

After the treatment has'been carried out as above outlined, thebeneficiatedm'aterialmay be distilled, as for instance; fatan upber wtebf' from 300 to'425" C. or higher te vdesired wood preservative as'a distillate, arnd'the residue if desired, alone, or mixed with fresh.

pitch to restore the volume; may be again'itre'ated The starting materials have toxicity induced therein as flowing from controlled action of hydrogen, whereby to provide, among other things,

lowered-poke residue, specifi c gravity and vissosie'. a Y

,ison Carbon of above 40 was subjected to treat tnent' with hydrogen in a continuous plant at 200 smiflflilwlz'cubic feet ofhydrogen per barrel of pitch.

s: belowspecii'lcation wood l preservative-are; formed; said low sends may #be 7 stripped to give conformance to said specifier tion wood reservative, as tax instance the-role ow n ispeclfivca iqn 0140131143118: i woon'ffimsmzvritojmediums, 1' Amerienwo i x 3; AmerioanWood Preser-vers Association:

9.. tsouthem Pine; shingle I stain Oil qiy.. at 137 0.,

10. Neville Shingle Stain Oil:

a. 7 LB. P., 15,0 C. anagram? C. 12-3 Z" 1'1- c r o i emn: v. .o

.1 2 G-"l- :B- 727 3 instead our-browsin thewocserpmservstive ss 4 adistillate; the entirety o the starting material mosphe'res, L the treatment; being cg injtinued for,

,The pitchabecause of its high carbon content mallyfcausedtlfiei'reaction chamber tovplug up 7-. ith-fleokef analysis of the situation dictated the procedurexiiicutting backthecarbon content of said pitchw'ith a low carbon coal tar fraction instancea medium boiling'fraction was seleete i==$nd $a=stficient amount wasadded to sternerterates the mixture to, a Conracison carbonof 25. this expedientdid not 7 However, entirely remove the difficulty. The pressure was ditimas remaining iaubstmhistly 2 17116 Ditm'hem'g Mmdhavine above carw th the thatokin onnditiom weme Mter r atm nt b pitcn in manner,

ma ia wwas to a 'limit :t n w-ieiethe-flristillnte as a wood a i preser ti the msuhinafm sa d dist lle ien w q e shmt bme er n fi at as nd nmxm eis Y a a n e' o :bQ &,:. $1 v a n s s hiecteda o theaction of hydrogen 7 st r s temperature of l75f I formation was evie ent-,1 An h -{P rm 1 inseam t nw m rea i ame we si ii W' h e ceritipn thatpressure was increased to ,600' :at-

threephours. No

. M Y, hep ioduct Sho eda. lowered CHM and a. "coal tar crfeosot'e' solutionIlgiavinig e ihan'ced toiiic value compared .with the starting material with ibenfi'ciation "substantially in excesses that secured at'fiobfatmospherespressure;- However, by variation; ofjcontrols, oil, comparable to, a creosote-coal} m,,sb 1;it1e having-a :higher poke residue" win (40% boiling at 355 o c. has been pntqi t fi d H p M l 'Eamii'ze"s :coa;1: tar, specific. gratit'y of: stafitially i t passd 'through ahreaction chamber at"425'c;. EIid'iIl excess area's atmospheres. pressure, while flowing in excess of cubic 'feetjof hyd'roogen or; hydroeen contaimng g as'p'er barrel of tar. "Time of reaction. Substantially one hour.

"Conradfsbh carbon of st ar'ting museu s '25.

"The rm i pmuuct' 1 had a, specific gravity. of in thef'order l lo a'nd' 'corira'dson carbon. of subowe'ver, catalysts on substan- AS l e i a e m b -menfi eemies- J t e ee ed;

i is fl ate'wc e pe tedmmourdii-' for three; without or 99 atmospheres and ithi-orjv-without; n derivative are n provide conformance more toxic.

" teases boilingprjedominantly above 355 c.) and having Conradson Carbontooihigh for said use. which comprises: subjecting said material torthe tox- ;stance, their oxides a'nd/ or sulphides alone or an admixture; J in combination. 1 with other. .materials efiectingfhydrogenation, or not, such as clays; silica, lumps ofjbrick, asbestos; etc.; supported on carriers including gels; in various forms, as .for instance, shapes; comminuted or as pellets or extruded lengths.-

V Example 4.,.--A -,tar, specific gravity; 1.16 .and

coke residue; specific gravity. and viscosity vtoo I high. for awood preservative was subjected to the action of hydrogenat 375 C. and {iouuatmos- .pheres pressure for 151minutes., At the end of the;1 5 minute period the temperaturewas raised to .440, G and continuedfor an additional'quarter hour. j 1

' 'I 'he hydrogenatedimaterial had in excess .of its parent material anda lowered coke residue, specificrgravity and yiscositythat made sameusable as-asubstitutefOr a creosote-coal tar solution. 4;% of lowends were removed to nthe. low boiling range t Said type oil. v,flhe present invention-is not circumscribed by any definite. boiling range of the wood preservavtiv es produced, and as will be immediately apent. o dx se v ne oils o wi e. and v ryin ,1 is permitted :by specificationsaccepted byrthe boiling ranges may be prepared from tars subheat t t x ci in udi g dro e a n- Example 3 shows as a starting material,; acoal tar having'a specificgrayity of substantially- 1.20.

As isle-well known, averagecolre oven tars seldom have thisspecific gravity, Thus the noted tar of 1.20 specific gravity was chosen from agroupof therefrom. f

residual' tars formed by removing fractions especially"attractive form ofjstarting ma- I 'terial is al tar orf'fra'ction thereof at.least once subjected ,to the refining action of hydrogen. When usingas a starting materials, or fraction thereof, at least oncerefined by hydrogen there is theadded advantage, among other thing's'thathigher temperatures be used, thusproviding an additional increment of de sired product.

.Minor changes may be made in .the stepsfof icityeinducing action of hydrogen while ,main- (taining a temperature chosen from the range in excess of 400 'C.'; thermally protecting and conserving those fractions'responsiblefor toxicity induction by coordinating .with said temperature a pressure in excess 0:200 atmospheres; protecting aromatic nucletfrom excessive rupture and destruction by 1 coordination of time, temperature and pressure, thetime being so selectedas'gto provide an oil containing, fractions necessary vin an -oil ofrthe. woodpreserving .type having not substantially (in .excess of 3% boilingyup -to'- =150 C.,' 'nor greaterrpercentages of-,Conradson Carbon or, residual materials distilling upto 355. -C. than trade for a .tar derived wood preservatives 3.VThe process of producing wood preservatives more toxicthan the starting material froma mixture of high temperature coal ta-r :fractions boils ing predominantly in excess of 355; Cr, having Conradson Carbon-and specificgravity too' high for! use as woodpreservative, and containing ,frac

tions once subjected to the action of hydrogen', which process. comprises: subjecting i said material to the, toxicity-inducing action of-hydrogen while; maintaining a temperature chosen from the range in excess of 400 .C.- thermallyprotecting and conserving those fractions responsible-for toxicity induction by coordinating with. said temperature apressure in excess 01200 atmospheres; protecting aromatic-nuclei from excessivelrupture and destruction by coordination oftime; ,temper-' atureand pressure-the time beingsoselectedasto provideranewly formed material of lowered spee cific gravity and Conradson Carbon, and induced toxicity, and: containing toxic. fractions necessary in an oilof the wood preservative type,"said cone tained toxic fractionshaving not more thanabout 0%.boi1i g-up to 210 C.,:nor greater, percents ages'of Conradson Carbon. or residual materials the process within the "scope of-the 'appended claims without departing from the spirit of the invention. k ,1 a.

Iclaim: 7 1.The process :of producing "wood pr'eserva tivesmorejtoxic than thestar ting material from a mixtureof high temperature coal tar fractions boiling predominantly above 355 C.' and having Conradson Carbon too'high for said use, which comprises: subjecting said material-to the toxicity-inducing' action 'of hydrogen whilemaintaining a temperature chosen from the range in excess of 400 C.; thermally protecting and conserving those fractions responsible for toxicity induction by coordinating with said temperature a pressure in excess'of 200 atmospheres; protecting aromatic nuclei from excessive rupture and destruction by coordination of time, temperature and pressure, the time being so selected as to provide an oil containing fractions necessary in an oil of the wood preserving type and having not substantiallyiin excess of 10% boiling up to 210? C.j, norgrea't'er percentages of Conradson carbon or residualimate'rials "distilling above 355? C; than is permitted by specifications accepted by the trade for a tar derived wood pre- Y a' i x The process of producing wood preservatives than' the starting material from; a mixture h fi P Qo ar fract ons distilling above 3559C. than is permitted by specificationsaccepted by, the trade for a tar derived wood preservative. j A 1 x 4. The process of producing woodpreservat-ives more toxic than the starting materialfroma mix; ture of hi hytemperature coal. tar fractionsboil-J ing predominantly in excess of 355- C.',;having Conradson Carbon and specific gravitytoo high for use as a Wood preservative, and containing fractions ;once subjected to the action of hydrogen, which process comprises: subjecting said material to the toxicity-inducing action of hydrogen while maintaining a temperature in exservative having no greater percentagtfiflf material boiling below 210 C., Conradson: Carbon nor residual material distilling above 355? C. than is permitted by specifications accepted; by the trade for a tar derived wood preserv ative.

5 Theprocess of producing woodpreservatives more toxic than the starting n'iatei' ial from a mixture of high temperature coal tar fractions boiling predominantly in excess of 355 0., having a o ra n -a ds e i av ty too hizh comprises: subjecting said material to the toxicity-inducing action of hydrogen while, maintaining a temperature chosen from the range in excess of 400 C.; thermally protecting and conserving those fractions responsible for toxicity induction by coordinating with said temperature a pressure in excess of about 1,000 atmospheres; protecting aromatic nuclei from excessive rupture and destruction by coordination of time, temperature and pressure, the time being so selected as to provide newly formed material of lowered specific gravity and Conradson Carbon,.

Conradson Carbon too high for said use, which s r a 5 Conradson Carbon too high for said use, which comprises: subjecting said material to the toxicity-inducing action of hydrogen while maintaining a temperature chosen from the range between a temperature in excess of 400 C., and

about 475 C.; thermally protecting and conserv I ing those fractions responsible for toxicity induction by coordinating with said temperature a pressure in excess of 200 atmospheres; protecting aromatic nuclei from excessive rupture and destruction by coordinating with said temperature and pressure a treatment period in the order of about fifteen minutes whereby to provide a newly formed material of lowered specific gravity and Conradson Carbon, and induced toxicity, and

containing toxic fractions necessary in an oil of the wood preservative type, said contained toxic fractions having not more than about 10% boiling up to 210 0., nor greater percentages of Conradson Carbon or residual materials distilling above 355 C. than is'permitted by specifications accepted by the trade for a tar derived wood preservative.

JACQUELIN E. HARVEY, JR.