GB2208166A

GB2208166A - Base precursor in form of salt and process for formation of a base

Info

Publication number: GB2208166A
Application number: GB8814516A
Authority: GB
Inventors: Yoshiharu Yabuki; Taku Nakamura
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1987-06-17
Filing date: 1988-06-17
Publication date: 1989-03-08
Anticipated expiration: 2008-06-17
Also published as: GB2208166B; DE3820595C2; JPH0759545B2; GB8814516D0; DE3820595A1; JPS63316760A

Description

1 BASE PRECURSOR IN FORM1 OF SALT AND PROCESS FOR FORMATION OF 'A BASE The

present invention relates to a base precursor in the form of a salt of an organic base with a carboxylic acid. The invention also relates to a process for formation of an organic base from the base precursor.

Bases are reagents which are widely used for various reactions such as hydrolysis reactions, polymerization reactions, color reactions, redox reactions, neutralizat.ion reactions, etc. For examiple, various recording materials such as silver salt photographic materials and diazotype pho.'klogra-ohic materials require a base during an imiage forming process.

An image may be formed on a recording material by a wet developing process using a treating solution (developing solution) or a dry developing process (e.g., heat developing process). A base may be contained in the developing solution, when an image is formed by the wet process such as a developing process. On the other hand, when an image is formed by a dry process, the base is previously incorporated into a recording material.

However, the base incorporated into the recording material sometimes causes a problem with respect to the stability of the recording material. For example, the base may adversely afflect the other ingredients in the 0 recording material or the base itself may be deteriorated during the storage of the recording material.

In order to eliminate the above-mentioned problem, it has been proposed to use a base precursor in place of the base. The base precursor is a neutral or weakly basic-compound and can form a base during the image forming process. In a heat developable recording material, a C; heat decomposition type base precursor is preferably used. Various kinds of the heat decomposition type base precursors have been studied and proposed. A typical examole of the heat decomposition type base precursor is a salt of an organic base with a carboxylic acid. The base precursors in the form of a salt of an organic base with a carboxylic acid are described in U.S. Patent No. 3,493,374 (triazine compound and carboxylic acid), U.K. Patent No. 998949 (trichloroacetate), Japanese Patent Provisional Publication No. 59(1984)- 180537 (propiolate) corresponding to U.S. Patent No. 4,560,763 and Japanese Patent Provisional Publication No. 61(1986)-l-1130 I.-sulfcnylacetate). These base precursors release a base when the carboxyl group in the carboxylic acid undergoes dec-arboxylationat an elevated temperature.

It has been requilfed' to find a base precursor which is stable during storage but is quickly decomposed 25- to form a base when it is heated. In the above-mentioned publications, prime attention is paid to decarboxyla tion of the carboxyl group of the carboxylic acid, and the carboxylic acid is mainly studied. However, these base precursors do not fully meet both of the two demands for stability during storage and for quick base formation.

9 It is an object Of the present invention to provide a base precursor which is very stable during storage (at room temperature) and rapidly releases a base when it is heated.

It is another object of the invention to provide a process for formation of a base wherein the base is rapidly formed from a very stable base precursor.

There is provided by the present invention a base precursor in the form of a salt of an organic base with a carboxylic acid, wherein the organic base is a diacidic to tetraacidic base which is composed of two to four L amidine moieties and at least one residue of a hydrocarbon or a heterocyclic ring as a linking group for the amidine moieties, said amidine moiety corresponding to an atomic group formed by removing one or two hydrogen atoms from an amidine having the following formula (I):

C, NR 1 R 4_ c R 2 N \ R 3 (i) wherein each of R 1, R 2 1 R 3 and R 4 independently is a monovalent group selected from hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group, each of which may have 1 2 3 one or more substituent groups, and any two of R, R, R and R 4 may be combined together to forma five-membered or six-me-mbered heterocyclic ring consisting of nitrogen and carbon atoms.

There is also provided by the invention a process for formation of a base comprising a step of heating a base precursor in the form of a salt of an organic base with a carboxylic acid, wherein the organic base of the base precursor is a diacidic to JL-, etraacidic base which is composed of two to four amidine moieties and at least one residue of a hydrocarbon or a heterocyclic ring as a linking group for the amidine moieties, said amidine moiety corresponding to an atomic group formed by removing one or two hydrogen atoms from an amidine having Lhe formula (I).

The base precursor of the present invention is characterized in that the organic base has two to four amidine moieties derived from the amidine having the formula (I). The Dresent inventors have noted that in order to improve a base precursor composed of a carboxylic acid and an organic base, prime attention should be paid t the organic base rather than the carboxylic acid.

According to study of the inventors, there has been discovered a base precursor -,-,hic,'-, satisfactorily func tions when the dLa--4-dic to tetraacidic base described above is used as the organic base. The obtained base precursor is very stable during storage and rapidly C C) releases a base at an elevated temperature. This surprising effect is explained belo-,,.

The salt composed of a diacidic, triacidic or tetraacidic base with a carboxylic acid has a stable crystal structure, compared With a salt wherein the organic base is a monoacidic base. Particularly, when the diacidic to tetraacidic base has a symmetrical structure, the crystal 30 structure is highly stable.

CD Further, a functional group accelerating decarboxyla:tion such as an aryl group is often introduced into the carboxylic acid of the base precursor. Consequently, the carboxylic acid generally has a hydrophobic residue. In 35 a salt composed of the carboxylilc acid having a hydro-- phobic residue and the diacidic to tetraacidic base, a plurality of the hydrophobic residue in the carboxylic acid are positioned around the organic base through ionic bonds. Accordingly, the base is located in the center of C, the salt surrounded by the hydrophobic residues of the carboxylic acid. The above-mentioned st;!uCture is much more stable as compared with the structure of a salt wherein the organic base is a monoacidic base, where the organic base and the hydrophobic residue of the carboxylic acid are positioned at both ends of the structure through ionic bond.

The present inventors have found that the base precursor composed of a carboxylic acid and an organic base melts or is dissolved in a binder contained in a recording material at an elevated temperature and then the carboxylic acid is initiated.

the decarboxylation of The base precursor Of the present invention has a stable crystal structure as mentioned above. Accordingly, the crystal. structure Of the base precursor is kepL until melts or is dissolved at an elevated temperature. Therelore, the carboxylic acid is rapidly decarboxylated to release. a b-_se at the same time that the crystal structure is broken.

I-Jhen the carboxylic acid has an hydrophobic residue, the carboxyl group of the carboxylic acid and the organic base are blocked by the hydrophobic residue in the base precursor of the present invention. Accordingly, the base precursor is prevented by the hydrophobic residue from being dissolved in a binder (which generally is C hydrophilic). The crystal structure of the salt is further stabilized by intermolecular interaction between th'e hydrophobic residues. Therefore, the base precursor of the present invention exhibits much higher stability during storage when the carboxylic acid has the hydro- phobic residues.

The diacidic to tetraacidic base derived from an amidine having the formula (I) is used as the organic base in the base precursor of the presen4Y- invention. Accordingly, the base precursor of the present invention releases the amidine derivative, which is a strong base, so that the relased base strongly functions in various systems requiring a base such as a recording material.

In the accompanying drawings:

Fig. 1 to 5 are graphs showing the results of the measurements of changes in the pH of the samples during heating, wherein the abscissa axis reDresents the heating Lime and the ordinate axis represents the p1HI.

Fig. 6 is a graph showing the results of the measurements of changes in the pH of the samples during 15) storage, wherein the abscissa axis represents the storage time and the ordinate axis represents the pH.

Fig. 7 is a graph showing the results of the measure-ents of changes in the pH of the samples during heating after storage, wherein the abscissa axis repre- sents the heating time and the ordinate axis represents the pH.

The base precursor of the present invention is in the form of a salt of an organic base with a carboxylic acid. The organic base has two to four amidine moieties in its molecular structure. The amidine moiety corresponds to an atomic group formed by removing one or two hydrogen atoms from an amidine having the following formula (I):

- 7 N-R 1 R A-C R 2 R 3 (I) 1 2 3 4 In the formula (I), each of R ' R ' R and R independently is a monovalent group such as hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group. Each of the monovalent groups may have one or more substituent groups. Among them, hydrogen, an alkyl group, a cycloalkyl group, an aralkyl group and an aryl group are preferred. Each of the alkyl group, the alkenyl group and the alkynyl group preferably has 1 to 6 carbon atoms. An example of the cycloalkyl group is cyclohexyl. An example of the aralkyl group is benzyl. An example of the aryl group is phenyl.

1 2 3 4 Any two of R ' R ' R and R may be combined together to form a five- membered or sixmembered heterocyclic ring consis.'-ina of nitrogen and carbon atoms (the the ring are only nitrogen and five.or six members o4L carbon atoms). It is particularly preferred that R 1 and R 2 are combined together to form a cyclic amidine having the followina formula (1-2):

C> R 17_ c R 15 (1-2) 16 In the formula (1-2), R15 is a divalent group such as ethylene, propylene, vinylene and propenylene. Each of the divalent groups may have one or more substituent groups. Among them, ethylene and propylene are preferred, and propylene is most preferred. In other words, 8 - the cyclic amidine having the formula (1-2) preferably is 2-imidazoline, 1,4,5,6-tetrahydropyrimidine or a derivative thereof, and more preferably is 1,4,5,6-tetrahydropyrimidine or derivatives thereof.

R 16 has the same meaning as in R 3 of the formula (I). -It is particularly preferred that R 16 is hydrogen or an alkyl group.

R 17 has the same meaning as in R 4 of the formula (I). It is particularly preferred that R 17 is hydrogen.

Another heterocyclic ring, aliphatic ring (e.g., cyclohexane) and/or aromatic ring may be condensed with the cyclic amidine having the formula (1-2).

In the present invention, the organic base of the base precursor is a diacidic to tetraacidic base which is composed of two to four amidine mo-Jeties corresponding to an atomic group formed by removing one or two hydrogen atoms from the above- mentioned amidine and at least one linking group for the amidine moieties. The linking f a hydrocarbon or a het g.-ouD Ls a residue oi- Uerocyclic ring. The linking group may have one or more substituent groups.

The amidine moiety preferably is a monovalent substituent group of a hydrocarbon or heterocyclic ring, as shown in the formula (!I) given below. In other words, it is preferred that the amidine moiety corresponds to an atomic group formed by removing one hydrogen atom from an amidine having the formula (I). However, the amidine moiety may correspond to an atomic group formed by removing two hydrogen atoms from an amidine having the formula (I). In this case, the organic base may,,be in the form of a condensed heterocyclic ring (Q.g., a tricyclic condensed ring).

In the base precursor of the present invention, the diacidic to tetraacidic base preferably has the following formula (!I).

9 - R 5 (-B) (ii) In the formula (II), R5 is an n-valent residue of a hydrocarbon or heterocyclic ring. The 'In" is an integer of 2 to 4. The 'In" preferably is 2 or 4, and more preferably is 2. When the 'In" is 2, it is preferred that the divalent residue of the hydrocarbon, which may constitute R5, is an alkylene group (more preferably having 1 to 6 carbon atoms) or an arylene group (more preferably, phenyl). An example of the residue of the heterocyclic ring, which may constitute R is a residue derived from pyridine ring.

The diacidic to tetraacidic base having the formula (II) preferably is symmetrical. In the present specifi- cation, the term of "symmetrical organic base" means that all of the groups represented by "B" are equivalent in the molecular structure of the organic base. In concrete expression, it means tha-11 no isomer is formed, even if the groups represented by "B" are replaced by dij4,'ferenL grcups.

In the formula (II), the group represented by "B" is a c. monovalent group corresponding to an atomic group forr.r,ed by removing one hydrogen atom from an amidine having the formula (I).

There is no specific limitation with respect to the position of hydrogen atom to be removed. However, when R 4 in the formula (I) is hydrogen, the hydrogen atom corresponding to R 4 is preferably removed. In other words, it is particularly preferred that the organic base 30 represented by the formula (II) is adiacidic to tetraacidic base having the following formula (II-1):

- N-R 21 R 24(C, R 22 n N \ R 23 (iil) 21 22 23 In the formula (II-1), R R and R have the 1 2 3 same meanings as in R, R and R of the formula (I).

R 24 and 'In" have the same meanings as in R 5 and 'In" of the formula (II), respectively.

Any two of R21, R 22 and R 23 may be combined together to form a a five-membered or six-membered heterocyclic ring consisting of nitrogen and carbon atoms. It is particularly preferred that R 21 and R 22 are combined,-her to form a diacidic to ' toge". Lletraacidic base having L.he following formula (11-2):

27 N \ 21- R (-C R 1 n (11-2) \ R 26 In the formula (1!-2), R25 and R26 have the same meanings as in R is and R 16 of the formula (1-2), respectively. R 27 and 'In" have the same meanings as in R 5_ and "n" of the formula (I!), respectively.

Examples of the organic base which can be used in the base precursor of the present invention are given below.

1 (B- 1) (B-3) 1 (B-5) (B-6) (B-2) c N N 3 NI In H H IQ) cy H \ N N:

H N - 0. N3 CN N H 0 H 8 N- CH 3 - -CH 2 CH 2---C H (B-4) N -CH 3 N H 0 N:

C NI N H p N H N N \/\-C H 2 CH 2 __3 c N N H H (B-7) (B-8) N N CH 3 N-) CH CH CH _c 2 2 2 \- 1 --/ N N CHN CN c 3 H H H H 12 - (B-9) (B10) (B-12) (B-13) GN -\//n H H c N CN N - H 0 N3 N H N N N3 H H CN -CH 3 N N -CH 2 CH 2-:)"- N H (B- 1 l) (B-14) CH 2 -CH 2\ N CH -3- N N3 N N 1 1 Uk.i 3 CH 3 N -D N CH 2 -CH 2\ N 0 N T 13 (B-15) CN c - i OCH 3 N CH 2 -CH 2\ N CH 3 o---. ---\<\ N (B-17) (B-19) (B-20) (B-16) CN -C H 2N "CH 2 -CH 2\ &CH 2', 3 (B-18) HN NH N c H \\C - C H -c Al H 2 N / \ NH 2 N C H 2 -CH 2 \ N N" HN H 2 N C-CH CH - c 2 -Q- 2 H 2 _ N3 UH 1 CH H l3 ICN - 2- - 2--- H N H 1 CH 2 -/ N3 H (B-21) N 1H HN \\ c -c // H 2 l / -CO \ NH 14 - (B-22) (B-24) (B-25) (B-26) (B-23) CINN N N N 0 H H HN \\C-CC, &NH / \ NH-10) NH CH N N_ -13 3 Cl 1 0 CH 3 l N C H N- N 1 1 U 2 h 5 C 2 H 5 (B-28) - CH C N CH CH /' N --- _ 2 2-- H3 H N H : (B-30) H (B-27) (B-29) - N- HO- - OH -N N _ H H H 3 -Co - C N N 1 1 Uh 2 CH 2 OH Uh 2 Uli 2 OH CN N:

(CH 2) 4_\ N H N H N N3 N N 1 1 U 2 h 5 C 2 H 5 1 r, - (B-31) Cz N N (B-32) N N '--, N N The carboxylic acid of the base precursor of the present invention should have such a property that the carboxyl group undergoes decarboxylation under certain conditions. However, carboxyl group generally has the above- described property so that various kinds of carboxylic acids can be used in the base precursor of the present invent ion.

In the case that the base precursor of the present invention is used for a heat developable recording material, it is preferred that the carboxyl group undergoes decarboxylation at an elevated temperature. The heating temperature required to deccarboxylate the carboxyl group preferably is in the range of 80 to 250 0 C, and more preferably is in the range of 110 to 200 0 C.

Exam;Ples of the carboxylic acids having the abovementioned property include trichloroacetic acid, pro- piolic acid and sulfonylacetic acid, which are described in the publications mentioned in the present specification at pace 2. It is preferred that the carboxylic acid has a functional group accelerating decarboxylation such as an aryl group or an arylene group, as mentioned

C.

above. The carboxylic acid preferably is a sulfLonylacetic acid having the following formula (III-1) or a propiolic acid having the following formula (111-2).

- 16 R31 1 Y(-SO 2 -CCO 2 H) k 132 R (III-1) -In the formula (III-1), each of R 31 and R 32 is a 5 monovalent group such as hydrogen, an alkyl group, an alkenyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group. Each of the monovalent groups may have one or more substituent groups. Among them, hydrogen, an alkyl group and an aryl 10 group are preferred. Each of the alkyl group, the alkenyl group and the alkynyl group preferably has 1 to 8 carbon atoms.

In the formula (III-1), Ilk" is 1 or 2. When Ilk" - group such as an alkyl group, a 1, Y is a monovalent.

cycloalkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group and a heterocyclic group. Among them, an aryl group and a heterocyclic group are preferred, and an aryl group is particularly preferred. Each of the monovalent groups may have one or more substituentil groups. Examples of the substituent, group of.he aryl group include a halogen atom, an alkyl group, an alkoxyl group, an alkylsulfonyl group, an arylsulfonyl group, an acylamino group, carbamoyl and sulfamoyl.

When Ilk" is 2, Y is a divalent group such as an alkylene group, an arylene group and a heterocyclic group. Each of the divalent groups may have one or more substituent groups. Among them, an arylene group and a heterocyclic group are preferred, and an arylene group is particularly preferred. Examples of the substituent groups of the arylene group are the same as those of the aryl group mentioned above.

i S 17 z (-c -----c 0 2 H) m (111-2) In the formula (111-2) 1, Z is a monovalent group such as hydrogen, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl groupY an aralkyl, an aryl group, a heterocyclic group and c arboxyl. Each of the monovalent groups may have one or more substituent groups. Among them, an aryl group is particularly preferred.

When "m" is 2, Z is a divalent group such as an alkylene group, an arylene group and a heterocyclic group. Each of the divalent groups may have one or more substituent groups. Among them, an arylene group is particularly preferred.

Examples of the carboxylic acid are given below.

(A-1) (A-3) (A-5) c-so 2 CH 2 CO 2 H C2- S02 CH 2C02 H Br- -so 2 CM 2 CO 2 H "m" is 1 or 2. When "m" is (A-2) (A-4), 0 0 0 so 2 CH 2 CO 2 H CH 3 so 2- -S02 CH 2 CO 2 H 18 - (A6) (A-7) Br c-so 2 -C-SO 2 CH 2 co 2 H (A-8) Br o0 so 2 CH 2 co 2 H CH 3 CONH- & so 2 CH 2 co 2 H (A-9) (A10) so 2 CH 2 co 2 H 0 so 2 CH 2 co 2 H co a so 2 CH 2 co 2 H (A- 11) CH 3 CONH 0 so 2 CH 2 co 2 H 0 (A-13) so 2 CH 2 co 2 H f (A-12) HO 2 CCH 2 so 2 (A-14) so 2 CH 2 co 2 H g0 0 1 N so 2 CH 2 co 2 H (A- 15) CH 3 CONH-.D-C-C-CO 2 H (A-17) HO 2 C-C-=c-cr--C=--C-CO 2 H (A-19) (A-21) (A-16) (A18) (A-20) I-D-SO 2 CH 2 CO 2 H C ú C A 0 so 2 CH 2 CO 2 H 0- C 1 &C--C-CO 2 H CH 3 0- C=_CCO 2 H CH - -SO CH--D 3 21 -;U2 H (A-22) CH 3 NSO i\-SO CH CO 2 2 2 1 (D - CH 3 The base precursor of the present invention is in the form of a salt composed o L' the abovementiQned carboxylic acid and organic base. There is no specific limitation with respect to a combination of the carboxylic acid and the organic base. However, it is preferred that the salt of the carboxylic acid and the organic base has a melting point of 50 to 200 0 C, more preferably 80 to 120 0 C.

Specific examples of the base precursor of the present invention are described below. However, the present invention is not limited to the following examples.

- 20 (1) (Cl-&SO 2 CH 2 co 2 E))2 H H -cn wn:) H (3) (5) H a0 so 2 CH 2 co 2 G) 2 0 H H N 11 G.

C:1N, ',- H H (4) (CH 3 so 2- -so 2 CH 2 co 2 0-)2 (2) (Br-&SO 2 CH 2 co 2 9) H H CN G E G N:) H H SO 2 CH 2 CO 2 9) 2 g0 o H 1 H -- 1 G,l:) n H H H CN G 0+ -CH 2 CH 2 N N H H H 21 (6) (7) (8) 0 so 2 0 Cb CCH SO p- -Q SO CH CO 9 2 2 2 2 2 2 H N G) N H H N c -CH 2 CH 2 H (CH 3 CONH 0 C=-C-CO 2 9)2 -g H H 0+ N 0 - N - M3 H (CH 3 CONH- & so 2 CH 2 co 2 9)2 H H H CN G) N H 1 H X (9) (10) (11) 1 so 2 CH 2 co 2 G)2 0 -9 H N 0 -CH 3 N CH 2 -CH - N CH 3 - n+ 0 H so 2- & so 2 CH 2 co 2 01) 2 H H N N- IN N H H so SO CH CO -)2 2-- 2 2 2C H H N 0+ N \/\- 2 2-- C H C H /j N H 3 H - 23 (12) (13) (14) (30 2 CCH 2 so 2---40 -S02- S02 CH 2C029 0 H H - C'I id H (0. so 2 CH 2 co 2 8) 2 0 00 0 eo 2 CCH 2 so 2 S H H H I c 'I\ 3 H 0 2 CH 2 co 2 G) H H H c C)-- H H N 24 - (15) (16) (17) (18) :o -CH=N--- S02 CH 2C02) H H N; 0 N c 1 --- N J H (C2- & CH=N- -so 2 CH 2 co 2 G) 2 H H H cp 3 H so 2 CH 2 co 2 9) 2 n+ H 0+ NH 2,\ 11H 2 \C c / CH 3 0-&NH / & \ NH-&OCH S02 CH 2C 0 2 G)2 1:5 H H CHCN G) -y CH 3 CH 3 N col N CH 3 H H - (19) (20) (21) 0-0 2 C-C-C-D-Cc-co 2 (E) H H C" l3 H H 0 so 2 CH 2 co 2 9) H H 0 N)- + CH 3 CH 2 CH 2- NC-C H 3 ---N N H H a0 so 2 CH 2 co 2 8) 2 H 0 cl C H 2 -CH 2., C+ H (22) N so 2 CH 2 co 2 8) 2 [(D H H CY--D 3 H H - 26 (23) (24) S02 CH 2C02 e) 2 H N 9 H G) N _ -CH 2 CH 2 N H H (25) 2 C-C=--C- -Cc-co 2 0-(C H 3 so 2 -&C=C-CO 2 9)2 H N 0+ 3 \- 0 / CN \ CC/ -- CH \-CH 2 2\ r;.,, 1 1 1 1 S 1 H (26) 114 (CH SO SO CH CO C-) 3 2--- 2 2 2 2 H H N 0+ CH CH C+ N C\- 2 2-- :N N H H H H lr- N G) 0 C+ N 3 N U+ N _+ CC N 1 CH CH 3 27 (27) (28) so 2-0 so 2 CH 2 CO 2 9) n- & H H CN 0+ (P N N Uh 3 CH 3 2 (CH 3 so 2--- D3-so2 CH 2 CO 2 9)2 H H 0+ 11 3 C H 3 Synthesis Ey ,ples of he base precursors (3) (5) are described hereinafter. The other base precursors can be synthesized in a similar manner as in the Synthesis Examples.

SYNTHESIS EXAMPLE 1 thesis of l-naphthalenesulfonyl chloride SynL In a mixed solution of 260 m2 of acetonitrile and 7 m of dimethylacetamide was suspended 133 g of sodium a- naphthalenesulfonate. While cooling the suspension with phosphorus oxychloride was dropwise added water, 80 m o-IL to the suspension. After the addition, the mixture was reacted at 65 0 C for one hour. The re'action mixture was cooled and poured into 2 A of ice-cold water. The precipitated grayish-white crystals were recovered by - 28 filtration and air-dried. The yield was 110.8 g (84.6 % of theoretical value), M.p. 66 - 68 0 C.

Synthesis of l-naphthalenesulfinic acid To 500 mú of an aqueous solution of 122 g of sodium sulfite was added 110 g of a-naphthalenesulfonyl chloride. While cooling the mixture with water, 20 % aqueous solution of 36 g of sodium hydroxide was dropwise added to the mixture so as to keep the reaction mixture at a pH of about 8. After about one hour, the reaction mixture became uniform. To the mixture was added 135 mú of 35 % hydrochloric acid was dropwise added. The formed grayish-white crystals were recovered by filtration and air-dried. The yield was 91.4 g (98 % of theoretical value).

thesis of l-naphthyl sulf onyl ace' Synt Cic acid (A-9) In 45 mA of isopropyl alcohol were suspended 44 g of l-na- iDhthalenesulif'inic acid, 17.4 g oj. potassium carbonate and 34.4 g of isopropyl chloroacetate. The suspension was heated to reflux for three hours. The reaction mixture was cooled,,and 20 % aqueous solution of 13.8 g of sodium hydroxide was added to the mixture. The mixture was stirred for one hour. The resulting solution was diluted with 58 mú of water. To the solution was added 58 ml of hvdrochloric acid. The precipitated crystals were recovered by filtration and air-dried. The yield was 54.9 g (95.8 % of theoretical value).

The crude crystals were recrystallized from 165 ml o- acetonitrile to purify it. The yield was 44 g, m.p.

L 168 - 172 0 C.' Synthesis of organic base (B1) In 600 mú of toluene were suspended 384 g of tere phthalonitrile, 533 g of 1,3-diaminopropane and 0.9 9 of 1 29 sulfur. The suspension was heated to reflux for 12 hours and then cooled to 70 0 C. To the reaction mixture was added 300 ml of methanol, The mixture was cooled to room tempera-Lure. The precipitated crystals were recovered by filtration and dried. The yield was 706.5 g (97.3 % of theoretical value).

The crude crystals were recrystallized from 3 1 of methanol. The yield was 567 g (78 % of theoretical value), m.p. 313 0 C.

Synthesis of base precursor (3) A solution of 41.2 g of l-naphthylsulfonylacetic acid (A9) in 120 mA of methanol was added to a suspension of 19.3 g of the organic base (B-1) in 160 m2 of methanol. The crystals precipitated from the resulting uniform solution were recovered by filtration and airdried. The yield was 55.0 g (92.7 % of theoretical value).

SYNTHESIS EXAMPLE' 2 Syntnesis of organic base (B-4) A solution of 40 g of succinonitrile, 100 m of 1,3-diam-Lnopropane and 0.3 g of sul-.Lur in 60 mA of toluene was heated to reflux for three hours and then cooled to room temperature. The precipitated crystals were recovered by filtration, washed with acetonitrile and dried. The yield was 95 g (98 % of theoretical value), m.p. 218 0 C.

Synthesis of base precursor (5) 1; A solution of 11.6 g of the organic base (B-4) in 20 m2 of methanol was added to a suspension of 36 g of p methylsulfonylphenylsulfonylacetic acid (A-4) in 150 M.2 of methanol. The mixture was stirred for one hour and 1 1 the formed crystals were recovered by filtration. The yield was 44.6 g (99 % of theoretical value).

The base precursor of the present invention is advantageously used in a process for formation of a base comprising a step of heating a base precursor. The base precursor is heated preferably at an temperature of 80 to 250 0 C, and more preferably at an temperature of 110 to 200 0 C. Further, the base precursor is preferably heated in the presence of a polymer (more preferably hydrophilic polymer). The polymer is preferably used in an amount of 0.5 to 400 weipj'.'It %, more preferably used in an amount of 1 to 200 weight %, based on the amount of the base precursor.

The base precursor of the present invention can be effectively used in various chemical reaction systems requiring base components, such as anionic-polymerizable adhesives, coating agents, sealing and caulking agents, as well as the aforementioned recording materials, such 1-1 CD -ype as silver salt photographic material---, diazct photographic materials. the The base formed from the base precursor of - invention can be used as a basic catalyst for the present -ion reaction of anionic-polymerizable mono- polymerizat L mers. There is no specific limitation with respect to the anionic polymerization, and the base precursor of the present invention can be widely used in the various products, such as adhesives, coating agents, sealing agents, caulking agents.

When the base precursor of the present invention is used in the above-mentioned products, a base can be formed by heating the base precursor for the use of the product. Accordingly, these products can be made neutral, safe and stable by using the base precursor of the present invention.

31 In the method using the diazotype photographic material, a coupling reaction between a coupler and the remaining diazonium salt in the unexposed area is carried out under alkaline conditions to form an azodye, as 5 shown in the following formula:

N 2 T + ArX (Colorless) (or ArOH in the presence of H 2 0) Light ArN 2 6-X_ + ArIOH (Diazonium salt) (Coupler) U Alkal i ArN=N-Ar'OH (Azo dye) When the base precursor of the present invention is used for the above diazo type photographic method, for example, employing a dry process, the base precursor and a diazonium salt are added to a diazotype photosensitive paper in such a manner that the diazonium salt and t-he base precursor are isolated fromm each other (e.g., by the solid dispersion of the base precursor). After the photosensitive paper is imagewise exposed, an azo dye image can be obtained by heat development. In conventional diazo type photographic methods employing a heat development, base precursors such as ammonium carbonate, hexamethylenetetramine are used. In the conventional methods, the developing time is relatively long and the light-sensitive paper has a problem with respect to the stability. Where the base precursor of the present invention is used in t1ae methods, the image can be rapidly formed and the photosensitive paper is improved in its stability.

In a conventional silver salt photographic process, the development (i.e., an oxidation-reduction reaction - 32 between silver halide and a developing agent) is carried out under an alkaline condition. Where the base precursor of the present invention is contained in the photographic material, the development can be carried out only by heating after exposure. In the photographic material, it is.preferred that the base precursor is isolated from other components in the photographic material by emulsifying, dispersing or encapsulating the base precursor. It is more preferred that the base precursor is dispersed in the form of fine solid particles. The base precursor of the present invention has another advantage in that it can be effectively isolated from other components in the photosensitive material.

Further, the base precursor of the present invention can be advantageously used in a light-sensitive material comprising a light-sensitive layer containing silver halide, a reducing agent and a polymerizable compound C, provided on a support. This light-sensitive material can be used in an image forming method in which a latent image of silver halide is formed, and then the polymerizable compound is polymerized to form the corresponding image.

Examples of the image forming methods are described in Japanese Patent Publication Nos. 45(1970)-11149 (corresponding to U.S. Patent No. 131,697, 275), 47(1972)-20741 (corresponding to U.S. Patent No. 3,687,667) and 49(1974) -10697, and Japanese Patent Provisional Publication Nos. 57(1982)-138632, 57(1982)-142638, 57(1982)-176033, 57(1982)-211146 (corresponding to U.S. Patent No.

4,557,997), 58(1983j)-107529 (corresponding to U.S. Patent No. 4,560,637), 58(1983)-121031 (corresponding to U.S. Patent No. 4,547,45-50) and 58(1983)-169143. In these image forming methods, when the exposed silver halide is developed using a developing solution, the polymerizable compound is induced to polymerize in the. presence of an X oxidized reducing agent to form a polymer image. Thus, these methods need a wet development process employing a developing solution. Therefore the process takes a relatively long time for the operation.

An improved image forming method employing a dry process is described in Japanese Patent Provisional Pub lication Nos. 61(1986)-69062 and 61(1986)-73145 (the con tents of both publications are described in U.S. Patent No. 4,629,676 and European Patent Provisional Publication No. 0174634A2). In this image forming method, a recording material (i.e., light-sensitive material) comprising a light-sensitive layer containing a light-sensitive silver salt (i.e., silver halide), a reducing agent, a cross-linkable compound (i.e., polymerizable compound) and a binder provided on a support is imagewise exposed to form a latent image, and then the material is heated to polymerize within the area where the latent image of the silver halide has been formed. The above method employing the dry process and the light-sensitive material employable for such method are also described in Japanese Patent Provisional Publication Nos. 61(1986)-183640, 61(1986)-188535 and 61(1986)-228441.

The above-mentioned image forming methods are based on the principle in which the polymerizable compound is polymerized within the area where a latent image of the silver halide has been formed.

Japanese Patent Provisional Publication No. 61(1986) -260241 describes another image forming method in which the polymerizable compound within the area where a latent image of the silver halide has not been formed is polymerized. In this method, when the material is heated, the oxidized reducing agent functions as polymerization inhibitor within the area where a latent image of the silver halide has been formed, and the polymerizable compound within the other area is polymerized.

34 - The polymerization reaction in the above-mentioned image-forming methods smoothly proceeds under an alkaline condition. Therefore, the,base precursor of the present invention can be contained in the light-sensitive layer 5 of the lightsensitive material.

The present invention is further described by the following examples without limiting the invention thereto.

EXAMPLE 1

In 80 g of 3 % aqueous solution of polyvinyl alcohol was dispersed 20 g of the following base precursor (3) using a Dynomill dispersing device to obtain a dispersion. A coating solution was prepared from 37 g of the obtained solid dispersion of the base precursor, 22 g of an aqueous solution of 5 % polyvinyl alcohol and 11 g of water. The coating solution was coated on a polyethylene Lerephthalate film using a - No. 40 wire bar in a coating amount of 7/0 cc/r.. 2 an,--'. dried at 410 0 C fo'r 30 minutes to prepare a coated sample of the base precursor (3). The sample was heated on a hot plate at f25 0 C. After a lapse of a given time, the sample was taken out and the pH on the surface of the film was measured. Further, the experiment was carried out by changing the heating to 75 0 C, 100 0 C, 140 0 C and 150 0 C. The pH was temperat.

2-5 measured at every ten records. The results of the measurements are shown in Fig. 1. Fig. 1 is a graph showing the relationship between the time and the pH obtained by plotting them. In Fig. 1, the abscissa axis represents the time and the ordinate represents the pH.

1 - 3 c; - (Base precursor (3)) 0 so 2 CH 2 CO 2 (9) 2 H H 0 N 6 87 C1m N 3 H EXAMPLE 2

H The procedure of Example 1 was repeated except that 20 g of the following base precursor (1) was used in place of 20 g of the base precursor (3) to prepare a coated sample of the base precursor (1).

In a similar manner to that described in Example 1, changes in the pH on the surface of the film upon heating were measured. The results of the measurements are shown in Fig. 2.

(Base precursor (1)) (CA -so 2 CH 2 CO 2)2 H H N N', 0 H H EXAMPLE 3

The procedure of Example 1 was repeated except that 20 g of the following base precursor (5) was used in place of 20 g of the base precursor (3) to prepare a coated sample of the base precursor (5). - In a similar manner to that described in Example 1, changes in the pH on the surface of the film upon heating were measured. The result's of the measurements are shown in Fig. 3.

(Base precursor (5)) (CH 3 SO 2- & S02 CH 2 CO 2 e) 2 H H CN N N H H COMPARISON. EXAMPLE 1 In 176.0 g of a 50 % aqueous solution of ethanol was dissolved 24.0 g of guanidine trichloroacetate (base precursor (x)). To the solution was added 176.0 g of 4 % aqueous solution of polyvinyl alcohol and the formed precipitate was dispersed in a Dyncx-,iill dispersing device. In a 'similar manner to that described in Example 1, the obtained dispersion was coated on a polyethylene tere- phthalate film and dried to prepare a coated sample of the base precursor (x).

In a similar manner to that described in Example 1, changes in the pH on the surface of the film upon heating were measured. The results are shown in Fig. 4.

COMPARISON EXAMPLE 2 The procedure of Example 1 was repeated except that 20 g of the following base precursor (y) was used in place of 20 g of the base precursor (3) to prepare a coated sample of the base precursor (y).

1 k In a similar manner to that described in Example 1, changes in the pH on the surface of the film upon heating were measured. The results are shown in Fig. 5.

(Base precursor (y)) aSO CH CO G 0 2 2 2 0 H cN D N H It is apparent from the results of Fig. 1 to 5 that each of the base precursors of the present invention rapidly releases a base when it is heated to 140 0 C or higher, but they do not release a base even when it is 15 heated at 100 0 C or lower for a long time. The conventional base precursor (x) releases a base slowly even at 0 C and it gradually releases the base a temperature of at a low temperature. The base precursor (y) rapidly releases a base at 125 0 C or higher, however, it gradually releases a base at a low temperature as in the base precursor (x). When the structure of the base precursor (y) is compared with that of the base precursor (3) of the present invention, the base precursor (y) is a salt of a monoacidic base having a similar structure to that of the base precursor (3) with the same acid as that of the base precursor (3). Accordingly, it can be understood that the decomposition behavior of a base precursor against temperature is greatly"changed by replacing a monoacidic base with a diacidic base.

-:)8 - - 1 EXAMPLE A

The coated sample of the base precursor (3) prepared in Example 1 was placed in a box made of a metal, sealed and stored at 50 0 C. After a lapse of a given period of time,-the sample was taken out and the pH on the surface of the film was measured. The results of the measurements are shown in Fig. 6. Fig. 6 is a graph showing the relationship between the pH and the storage time obtained by plotting them on the basis of the measurement results. In Fig. 6, the abscissa axis represents the storage time and the ordinate axis Cz.

represents the pH.

EX.PI.1PLE 5 The coated sample of the base precursor (1) prepared in Example 2 was stored in a similar manner to that described in Example 4, and the pH on the surface of the film. was measured. The results of the measurements together with those of Example 4 are shown in Fig. 6.

CD 11 EX-C4PLE 6 The coated sample of the base precursor (5) prepared in Example 3 was stored in a similar manner to that de scribed in Example 4, and the pH on the surface of the film was measured. The results of the measurements together with those of Example 4 are shown in Fig. 6.

COMPARISON EXAMPLE 3 The coated sample of the base precursor (x) prepared in Comparison Example 1 was stored in a similar manner to that described in Example 4, and the pH on the surface of 7.

1 - 39 the film was measured. The results of the measurements together with those of Example 4 are shown in Fig. 6.

COMPARISON EXAMPLE 4 The coated sample of the base precursor (y) prepared in Comparison Example 2 was stored in a similar manner to that described in Example 4 and the pH on the surface of the film was measured. The results of the measurements together with those of Example 4 are shown in Fig. 6.

It is apparent from the results of Fig. 6 that the base precursors of the present invention do not release any base under Storage conditions at 50 0 C, while the conventional base precursors (x) and (y) release consider- k, able amounts of bases for a storage time oil o.nly one day at 50 0 C.

EXMAIPLE 7 The coated sample of the base precursor (3) prepared in Exampl,e 1 was stored under the storage conditions of Examiple 4 for 8 days and then heated to 140 0 C on a hot plate. After a lapse of a given time, the sample was taken out and the pH on the surface of the film was measured. The results of the measurements are shown in fig. 7. Fig. 7 is a graph showing the relationship between the time and the pH obtained by Plotting them on the basis of the measurement results. in Fig. 7, the abscissa axis represents the time and the ordinate axis represents the pH.

- 40 EXAMPLE 8

The coated sample of the base precursor (5) prepared in Example 3 was stored under the storage conditions of Example 6 for 8 days and then heated at 140 0 C on a hot plate.- After a lapse of a given time, the sample was taken out and the pH on the surface of the film was measured. The results of the measurements together with those of Example 7 are shown in Fig. 7.

It is apparent from the results of Fig. 7 that the base precursors of the present invention hardly cause a lowering of base - forming function when they are heated, even after they are stored under severe conditions for a long tirre.

1 n 41 -

Claims

CLAIMS:

1. A base precursor in the form of a salt of an organic base with a carboxylic acid, wherein the organic base is a diacidic to tetraacidic base which is composed of two to four amidine moieties and at least one residue of a hydrocarbon or a heterocyclic ring as a linking group for the ar.-iidine moieties, said amidine moiety corresponding to an atomic group formed by removing one or two hydrogen atoms from an amidine having the 10 following formula (I):

N-R 1 R 4- c '/ M) NI \ R 3 (I) 1

2 3 4 wherein each of R R ' R and R independently is a monovalent group S e Le c t e d f r o.-,i hydrogen, an alkyl group, an alkenyl croup, an alkynyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group, each of which may have 1 2 3 one or more substituent groups, and any two of R ' R ' R and R 4 may be combined together to form a five-membered or six-,-..ie-ibered he'-, erocyclic ring consisting of nitrogen and carbon atoms.

4 2. The base precursor as claimed in Claiin 1, wherein the organic base is a diacidic to tetraacidic base having the following formula (II):

R 5 (-B) (II) wherein R 5 is an n-valent residue of a hydrocarbon or a heterocyclic ring; B is a monovalent group corresponding to an atomic group formed by removing one hydrogen atom from an amidine having the formula (I); and 'In" is 2, 3 10 or 4.

3. The base precursor as claimed in Claij-,i 1, wherein the amidine having the formula (I) ils a cyclic Cormula (1-2):

amidine having the following f N is R 17 -c \ R 15 (1-2) N 16 1:, 1 1 C, wherein R is a divalent group selected from the group consisting of ethylene, propylene, vinylene and propenylene, each of which may have one or more substituent groups; and each of R 16 and R 17 independently i- a monovalent. group. --.selected f roin hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl. group, an aralkyl group, an aryl group and a heterocyclic group, each of which may have one or more substituent groups.

S:

4. The base precursor as claimed in Claim-1, wherein the amidine having the formula (I) is 1,4,5,6tetrahydropyrimidine, which may have one or more 11 substituent groups.

c - 4 3 - r'. The base precursor as claimed in Claim 2, wherein the organic base having the formula (II) has symmetrical chemical structure.

6. The base precursor as claimed in Claim 2, 5 wherein 'In" in the formula (II) is 2.

7. The base precursor as claimed inClaint 1, wherein the organic base is a diacidic to tetraacidic base having the following formula (II-1):

N-R 21 R 24 (-C / R 22) (II-1) n N \ R 23 21 22 23 wherein each of R I R and R independently is a nionovcLlent.. group selected from hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group, each of which may have 21, 22 one or more substituent groups, and any two of R, R and R 23 may be combined together to form a five-membered or six-membered heterocyclic ring consisting of nitrogen 24 ' a and carbon atoms; R is an n-valent residue oL hydrocarbon or heterocyclic ring; and 'In" is 2, 3 or 4.

4

8. The base precursor as claimed in Claim 1, wherein the organic base is a diacidic to tetraacidic base having the following formula (11-2):

N R 27 (-C // \ R 25)n (11-2) N 1 26 wherein R 25 is a divalent group selected from ethylene,. propylenet- vinylene and propenylene, each of which may have one or more substitCuent groups; R 26 is a monovalent group hydrogen, an alkyl %3rollp, an alkenyl group, an alkyny! group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group, each of which may have one or more substituent, groups; R 27 is an n-valent residue of a hydrocarbon or a heterocyclic ring; and 'In" is 2, 3 or 4.

9. The base pre=sor as cla.Lued--in any preceding claim, wherein the carboxylic acid has such a property that the 20 carboxyl group of the carboxylic acid undergoes decarboxylation at an elevated temperature of 50 to 200 0 C.

10. The base precursor as cl-aimed in any preceding claim, wherein the carboxylic acid has an aryl group or an arylene group.

r 1 t

11. The- base precursor as claimed in. any preceding clai;;i, wherein the carboxylic acid has the following formula (III-1):

R 31 1 Yk-SO 2-UCO2 H) k (III-1) 132 R wherein each of R 31 and R 32 independently is a monovalent group selected from the group consisting of hydrogen, an alkyl group, an alkenyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group, each of which may have one or more substituent groups; IW' is 1 or 2; when IW' is 1, Y is a monovalent group selected from the group consisting cycloalkyl group, an alkenyl group aralkyl group, an aryl group and a each of which may have one or more and when IW' is 2, Y is a divalent the group consisting of an alkylene group and a heterocyclic group, each one or more substituent groups.

of an alkyl group, an alkynyl group, heterocyclic group, substituent groups; group selected from group, an arylene of which mav have

12. Thebase- trecursor as el.aiLwd in arly preceding claim, wherein the salt of the organic base with the carboxylic acid has a melting point of 50 to 200 0 C.

13. A base precursor as claimed in any preceding claim, wherein the organic base is any of bases (13-1) to (B-32) shown hereinbefore.

14. A base precursor as claimed in any preceding claim, wherein th( carboxylic acid is any of the acids (A-11) to (A-22) shown hereinbefore.

15. Any of the base precursors (1) to (28) shown hereinbefore.

16. A method of synthesising a base precursor as claimed in any preceding claim, substantially as herein before described.

17. A process for formation of a base, comprising heating a base precursor in the form of a salt of an organic base with a carboxylic acid as defined in any preceding claim.

18. A process as claimed in Claim 17, wherein the base precursor is heated at a temperature of 80 to 2500C.

19. A process as claimed in Claim 18, wherein said heating is at a temperature of 110 to 2000C.

20. A process as claimed in Claim 17, 18 or 19, wherein the base precursor is heated in the presence of a polymer.

21. A process as claimed in Claim 20, wherein the base precursor is heated in the presence of. a hydrophilic polymer.

22. A process as claimed in Claim 20, wherein the base precursor is heated in the presence of a polymer, said polymer being used in an amount of 0.5 to 400 weight % based on the amount of the base precursor.

23. A process as claimed in Claim 17, substantially as hereinbefore described in Example 1, 2 or 3.

24. A base formed by the process of any of Claims 17 to 23.

25. A process of polymerizing an anionic monomer wherein a base as claimed in Claim 24 is used as catalyst.

26. Photographic material which includes a base precursor as claimed in any of Claims 1 to 15.

Published 1988 at The Patent Office. State House, 66 71 High Holborn. London WC111 4TP. Further copies may be obtained from The Patent Office. Sales Branch, St Mary Cray. Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray. Kent, Con. 1/87.

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